followup.
was at a gun show this am.. and found a guy selling odd bits.. found some front blade dovetails.. he had a single one in 3/8.
took it home, scraped the gunk and crud off it and it feels like it's gonna be agood press fit for my 592
still for the life of me can't figure out how mine came out? were the original plastic? I havn't shot the thing in?20 ys or so...