Ground dug fakes appeared as soon as the Soviet Union broke up! Early 1990s there were still plenty of origials coming up from the ground. By the mid / late 1990s you were seeing more fake dug rings than originals! Now I'd hardly trust any unless I dug them myself, or they had some sort of provenence from someone I trust.
I have a small section in my 'Fakes, Frauds and Postwar' chapter of my book for 'Ground Dug' fakes...
Here are a few test shots.. This is a typical bad reproduction from a few years ago.
