Hello again, Spikey.

First, let me correct an oversight on my part and welcome you to Nitro Express Forums (as had Louis).

When I initially found this 'site, with its dedicated Mannlicher thread, I knew I was in the right place.
Please tell other MS owners, enthusiasts, and other interested parties about NE, as much of the other 'information' you'll find on 'gun forums' (particularly U.S. based) will range from somewhat inaccurate to pure garbage. I began posting on some of them a few years back to replace myth and damaging advice with facts and knowledge which was appreciated by some, vilified by others.

These days I post here and to Africa Hunting (you may want to give this one a good read: https://www.africahunting.com/threads/ma...velocity.47277/ ) and have left a lot of information at The Firearms Forum before being 'banned' for not dancing around a moderator's ego: https://www.thefirearmsforum.com/threadloom/search?query=mannlicher&tab=3908 . Beware, however, of well intended but ill informed posts on that 'site (and others), though their member Sharps 4590 (also a member here) is informed and casts bullets for his M1908 (8X56).

Your .30-'06 chambering lets you out of the difficulties of making your own cartridges, as many of us must do for MS obsolete calibers (mine is 9.5X57), so you're fortunate there.

Stock

The Mannlicher Schoenauer was introduced at the Paris Worlds Fair of 1900, in fine 'sporting rifle' form, but was always intended to be a military arm and was marketed to compete with the Mauser 98 'head on'. Prototype models of M1900 were produced, in rather small numbers, in 'sporting' and in military formats and shopped to various ordnance departments. Largely due to its unit cost, the only major military customer was Greece.

The 'sporting rifle' prototypes had caught the eye of some top tier British gunmakers and soon 'bespoke' versions of the MS were being crafted by Westley Richards, Gibbs, and the like several of which were built from highly finished military examples.

With the Greek contract secured for a 1903 revision of the military model, the Mannlicher Schoenauer entered production at Oesterr Waffenfabriks Geshellschaft Steyr in 1905 with the Y1903 which would be followed, through the years, by Y1903/14, Y1903/27 (Breda), 'System 1930', and some smaller run variants.

M1900 prototype, military (note hand guard and thick stock)

Mannlicher Schoenauer Y1903 'Greek' variants

With full production of the military contract underway Steyr also produced their own sporting versions, much the same as Mauser did with their 'Oberndorf' models. The M1900 had incorporated a unique MS proprietary cartridge, the now famous 6.5X54. Civilian production would begin with the M1903, also in 6.5X54, and the M1905 in a new MS proprietary 9X56 cartridge.

The pre WW2 Mannlicher Schoenauer sporting arms left the Steyr factory with one of three styles of stock, a stutzen (full stocked carbine), a half stocked rifle, or a dandy little take down system they seem to have pilfered from Westley Richards (or vice-versa).

Here, in the 1939 Stoeger, are represented the original stock styles:

As the Anschluss (Nazi occupstion of Austria) took effect in 1938, production of sporting arms at Steyr was curtailed, but did continue.

When production of the Mannlicher Schoenauer resumed in 1950 the 'Take Down Model' was dropped as stutzen and half stocked rifle styles continued on essentially the prewar profile, though without the trap door buttplate of prewar years.

From 1954 - Single or double set triggers had been available from the beginning on all but the Take Down Model, which had the single trigger. Notice also the 'shotgun style slide safety'. MS safeties were undergoing revision at the time the M1952 was in production.

Steyr needed to court the U.S. post WW2 market and Yanks liked scopes which led to changes in the comb area of post WW2 Mannlicher Schoenauers.

About 1956, the 'Monte Carlo', or MC stock was introduced with a high, sculpted, comb more suitable for use with a rifle scope.

For those who preferred the previous type, they continued on as the 'GK' option:

Mannlicher Schoenauer GK

By 1961, an 'MCA' or Monte Carlo All Purpose was offered as an intermediate height compromise for scope or iron sight use.

Your MS should have a model designation on the front bridge. If it is marked 'Mod. 1952' it came originally with a straight comb stock as there was only that variety for that model.

Your stock tip (I'll presume it's a half stock?), if original, should be buffalo (not bison) horn. The only plastic to be found on a genuine Mannlicher Schoenauer was in the white line spacers that were a passing fad of the 1950s-60s and, perhaps, stock varnish.

A sight hood was optional for the MS, so it's not like you're actually 'missing' one. I'd love to find an original (or even accurate repop) of the 'prewar' version for my M1910 Take Down.

One 'hard and fast' rule about Mannlicher Schoenauers is that there seem to be few hard and fast rules about Mannlicher Schoenauers. There were custom options available throughout production of all models and anomalies abound.

When disassembling your MS, use proper fitting (thin bladed) drivers!
Instructions for disassembly (scroll down): https://www.mannlicher.org/mannlicher-characteristics.html

If you have further questions (you will), you now know where to come for answers. There are several members here with hands on experience regarding the Model M1952 and any other MS about which you may be curious. Member Kuduae is an authoritative source of information regarding any European sporting arm of the Twentieth Century and then some.

Enjoy!

P.S.:
I have absolutely no idea about the '5420' marking on your scope mount, but by your description and the model involved it's likely a 'factory' installation.