I’ve got a double long spring with webbed jaws. I was told it’s a Herters. My guess is a #11? Would anyone have a pan for it? It’s missing, the rest of the trap is good.

Is this a Herters? Where would I find a original pan for it?

Iam guessing it would be a Herters by the jaws and pan shank. To get a pan for that trap is going to be hard unless someone in Minnesotta might have a stash of parts. Herters where sold out of Minnesotta so I would ask those guys first.

You might luck out and find another trap like it that’s damaged with a good pan. The nationals or Sydney maybe.

I would be surprised if that were a Herters. If I recall, the only trap they made with cast jaws like yours was a 2 1/2 single spring. I think they called it an otter trap. I remember seeing them in a Herters store back in the 70's. I remember thinking at the time that all their other traps were junk.
I'd like to see the rest of your trap, but the "pinched" form of the cross bar (to hold the pan) reminds me of some old Blake and Lambs I used to use.

I was told if should be a #42 Herters

There are three or four of those traps for sale on eBay right now so it is possible to compare.

If it is a Herters, it should be stamped on the under side of the frame.

Should say “Japan” and “Hxx”. The xx being 2 numbers, like H77.

It has H71
Japan