Kelump, I remember these stamps used to be common in packets 40 years ago but aren't seen so often these days. I prefer to collect them mint because the postmarks are too dubious. Watch out for stamps which are either "too good" or really crude execution as these are also likely to be forgeries.
All these Caucasian Republics are thick with forgeries, especially early Armenia overprints. It seems the forging may also have been done by the postal staff themselves, simply to keep the philatelic market supplied. Deep, dark and murky...
Here's the first issue on greyish paper (as Tvorog mentions). I'm missing a few issues on white paper.

tOn the other hand, These next stamps are often seen, but they are completely bogus.
