Second pattern 1892, but I've NEVER understood the "why".

That is the plate on 20196, which is otherwise 1892, with changes to date (cutaway bolt rib, bevelled cocking piece, etc.). The stock is crudely relieved to clear the unfinished cover-plate lugs.

Were some guns assembled hastily for some reason, not waiting for the full implementation of the improvement? Seems odd for a piece with an 1896 sight, and very clear JSA/1896 cartouche. We know they were held up for the sights - why not do the butt properly at the same time?

Another mystery.