Or take it out of a old fender that has one that the fender is shot in other then the well itself.
As I'm lucky enough to have just that or you could call Steve at Bert's as he might sell you one of what you need as I know he has about a million part's out there from fenders on up anything you want he more then likely has it.
I know someone around me that's always buying those fender wells as he put's them in the fenders I don't know if he still doing it though haven't talked to him for a few years now.
Good luck on your quest
Bert's web site is Bert's model A center
Reggiedog