The info I have says that they were in production from 1978-1992, they only made one model
321, Camillus Contract, blade stamped BUCK/321/USA, Brass liner, No spacers, No handle pins, Brass rivet, Short pull nail nik, 2 back springs, Ellipse Escutcheon, Flat grind, Attached bolsters, produced from 78-'92, and, EZ Open Notch For Master Blade, with Gut Hook.