On commercial Mannlicher Schoenauer sporting rifles from England/Europe, many times there will be a number stamped into the buttstock, often along the toeline of the stock. Here is an example of a description from a Mannlicher Schoenauer rifle that sold at auction over the weekend: ".... the toeline of the stock is stamped ''Y5315'' just to the rear of the factory sling swivel." The number "Y5315" is not the same as the rifle serial number.
In addition on a recent purchase of mine, a M1910 M-S rifle in .375 Rimless Express with London proof marks is a serial type number stamped on the toeline near the rear swivel. This number, again, does not match the action serial number.

The question is does anyone know what these added numbers were for? I have heard some conjecture on the subject that these rifles were part of the India trade, however, I want to know if anyone could add to determining an answer concerning this number. Thanks in advance