Dumb question - but what happened to the original??
I would suspect you will be more successful in repairing the original than finding a new one. Metal can be added to (welding) and then removed (filing) to turn it into pretty much anything.
If you are in a jam I do know a gunsmith in the UK who can recreate basically any part of a shotgun.
Still searching, holding out some hope that one will surface. I have spoken with Larry D. and the fine folks at Turnbull (and a number of other likely sources as well).
A forum community dedicated to Trap shooting enthusiasts. Come join the discussion about targets, clays, hunting, gunsmithing, gear reviews, accessories, classifieds, and more!