An M1903 sporting rifle or stutzen should have proofs that look a lot like this:

On the above example, the 411.08 indicates the 411th arm to be 'nitro proofed' in 1908 at Vienna.

The magazine parts can often be found on Ebay as the more common Y19093 (Greek military contract MS) and variants used the very same 6.5X54 magazine. Parts interchange fully with those and the particular part that is 'uglied' on yours is the same across the M1900 through M1910 models.

Original M1903 stocks occasionally show up on Ebay as well. To find a modern craftsman that can fashion a stock with the subtle finesse, cast, and svelte balance of a pre WW2 MS may prove to be quite an endeavor. Perhaps consult with Joel Dorleac for advice in that regard?

This complete M1908 stock is listed now on Ebay, though at $900 USD ("or make offer"): Ebay

There is also presently listed an M1903 Magazine, complete:

Ebay

It is worn and the floorplate appears to be altered (ground), but illustrates the interchangeability between Y1903 and M1903 parts.

Separate components of Y1903 magazines do show up frequently on Ebay, but I do not see the part you need by itself just now.