As far as I know, '80s Zs aren't that sought after, unless they are EAKs. It really boils down to the weight and tonal qualities.
I suppose it's a 20"? Would be easier to judge the price of your cymbal with pictures and possibly a sound clip.
The most popular vintage Avedis Zs are the Trans stamps, followed by '50s (can't remember which stamp), the EAKs and then the '70s I think.