[lugerholsterrepair]

I realize it would merely be speculation until one saw it firsthand. Not really. 1918 stocks do not have the Crown S as they were made during the WW1 conflict but were never accepted by the Military. Quite often I have seen them where they are not fitted to the pistol they are numbered for either. Yours has likely been fitted though as it fits a pistol you have..Artillery stocks once fitted will fit about half the pistols you try it on. Not all of them though.

Most collectors like to see the Crown S acceptance stamp. They mostly pay less when there isn't one. Or pay more for the rare Crown G. All this being the case I suspect your stock might bring $550-650 or so if offered on eBay. Then eBay is going to slice off the top including shipping 15-20% This market fluctuates slightly month to month. But that's just an educated guess.