Haven't had to resort to epoxy yet. The plastic trigger came on a beater 13-89 backpacker I had bought used at a gunshow. It was one of those transition guns that Crosman couldn't quite make up their minds on, with the phase 2 hammer pictured, and plastic trigger. The original tube was cut for a hammer pin. My best guess is early to mid 70's for production. It also had a swinging gate pellet holder, instead of a bolt...
Regards,
Doc Sharptail