I think I have the same flag as Comrade in the second picture, which is seemingly a "cheap repro". I bought it from a seller who claimed in was legitimate, though upon arrival I noticed that the Hammer & Sickle and the star were not of the correct proportions. Furthermore, the symbols are printed onto the red fabric in the same way that images are pressed onto T-shirts (the name of the technique forgives me), they are not woven into the fabric.
That is what the tag looks like. I was incredibly discouraged upon seeing the english on the tag, though considering it is apparently for "1 May" I thought it might have been made for export to provide for left-wing groups overseas in May Day events.
So is this a tacky reproduction or a proper Soviet flag?
Definitely a repro, says right there made in 1978 (r).