I have alot of love for german guns. Like the older one,s best. On my list so far is a 1962 diana 35 great open sight shooter an my new daina 25 from 1966 sweet an the clone of diana 25 in 22cal a dasiy 250 made in scotland by milbo it,s my farvorite one mid 400 fps an deadly with dasiy wad cutter. the dasiy is a 1964. wish they still make them great gun.
Looks like a model 24 Diana. Sure it's not marked? The F in the Pentagon denotes is to verify that the gun meets the 6fpe German limit. (Imposed on air guns following the elimination of the Israeli athletes during the Munich Olympics.) That is, if the gun were sold within Germany. Export guns are also so marked but are full power, depending upon where they are sold to. Must be easier to just mark them all.BTW, $50 would not even get you in the door for an R1 twenty years ago. They might possibly be cheaper today.