I miss the bar in the stock, that fits to the slot under the barrel.

So stock and barrelled action will probably not come of the same house.

The Argentine magazine box maybe a later ad.

Though there were a few civilian Mauser rifles made around 1920 with that boxtype.

The lack of any markings make it difficult to identify the maker and date of making.

I wonder if there are no proof marks , at least under the barrelshank.