I think your hinges might be the same as
Scamp hinges
since they have three fasteners on the camper side. Bolers have a similar type but with only two fasteners on the camper side.
Scamp sells hinges complete, or kits to rebuild the guts (which also work on the
Boler hinges).
Scamp has a website, but best just to call them for parts. 800-346-4962.
Couple of notes:
1) It seems that they use non-stainless bolts and nuts in the hinge kits, so you'll probably want to substitute different ones when you get them.
2) One "set" is one hinge, not a set of two hinges. Also, I *think* that hinge #2 goes on the bottom, and hinge #1 on the top, but you can probably check how they match up to the ones you're taking off.
Their prices seem reasonable, too.
Rachel