Universal Sptg.Russian Import shotgun

I have an "Universal Sporting Goods" Russian( Tula;possible name of Factory) double-eared 20" barrel, 2 3/4", shell, Coach 12 guage sidexside,shotgun, with an number of C-700 imprinted on the inside of breech. There are various hunting designs, birddogs, gamebirds, and scrolls, engraged on the thumb piece, on top of the breech housing and on both lock plates. I am asking if anyone of the experts have information on the Date of Manufactuer, where, when these Coaches double-barrels were first imported and last imported. Is Universal still around to buy parts, or is there another resource I can tap into or with? I really appreciate it, if someone knows of the current value and if it is alright to fire any type of modern shot shells in this weapon, If I ever have too? Thanks so much.