If it has a shaped butt end, ie: not flat, then looking for a matching butt plate makes some sense.
If it has a flat end on the stock, measure the dimensions, and buy a universal replacement plate and have it installed and be done.
But you never know, you could get lucky and hook up on one.
I don't think it would make any real difference to a guy buying it whether it was original or not. If it was well installed.
Cheers
Trev