Not 1970s.The hammering on this cymbal from mbira is a giveaway that it is not a 70s Avedis Zildjian. Drumaholic told you, but he didn't include all his reasoning. But I'm very happy with his judgement. I think we are on the wrong track with this idea that heavy polishing or abrasive cleaning at the level that cymbal shows could remove all traces of a stamp. I'm not seeing complete and utter destruction. Just some superficial scratching. I can't be sure, but it seems more likely to me that it just didn't get a stamp at the factory. I've never seen a 1970s stamp which would "rub off after a few cleanings". But then I haven't seen that many Avedis cymbals, and I've cleaned many fewer than that. Has it actually happened to you redneckdrum? Using what sort of cleaner?
Well, it's takes more than a few cleanings to wear down a stamp to the point to where its almost invisible but in my younger days when I was obsessed with cymbal cleaning I had a Paper Thin Crash where I nearly completely rubbed the stamp almost off. It was your run of the mill amonnia based cleaner such as the Zildjian cymbal cleaner.