I have a 1322 Medalist, with wrap around grips, rear cocking. It also has the reddish marbled grips, pump handle. Rough guess would be early 90's. I do recall the rear cocking, sliding breech still being made in the mid-90's, because I bought a new backpacker, with those attributes in 94, or 95.
Look at the printing date on the instruction sheet. That should give you a rough idea, seeing as the medalist was the granddaddy of the 1300 series.