Regarding the "Made in Austria", my 9x56 M-Sch was made in 1920 and it doesn't have this marking either. Later rifles I checked, (made 1925 and after) do. So I suppose at some stage around those years "Made in Austria" was added on.

If the same style "213" number appears on bolt, receiver and barrel, then surely they're all factory fitted and original. Looking at my 9x56 M-Sch., the NPv marking appears just below the British N P mark with the hand-held cutlass above it, (which is what seems to be in your photo too), just on the stock line, (LH side). Why NPv isn't below this on yours is a mystery to me.

Apparently, according to Nonte's Cartridge Conversions, you can use 8x57 Mauser dies to make this case, just lower the die further until the bolt will close on the case. I've heard of people taking some metal off the shellholder to achieve this. In that way the die is still OK to use with 8x57 Mauser cases. If you modify a Mauser die, it might be an idea to mark it to show the modification was made. I mention this in case the cost of a special custom 8x56 M. Sch. die set is putting you off reloading.