As a rule of thumb :
Pre WW1 : Horn with Mauser Logo as alphabetic character
Post WW1 starting with horn til the end of production plastic with "ton" Mauser Logo
The buttplates for the .22 Sporting rifles nearly identical in dimension but were flatter.
The classic sporting rifles had a greater radius.
Some of reproduction buttplates had no "diamonds " around the screw holes.
Steel buttplates with trap mostly found on Type M Stutzen ( But also some on semi stocked rifles ).
Steel buttplates without trap but with Logo relatively seldom.

For a reproduction rifle I would follow eagle27.