Let's see what ya got!
It is a 20 " 1870 g ride , has a 6-number seial starting with 3, below or above the serial(below the bell) is nothing, so I think it's from 1973. But except for the stamp (in the 3 o'clock position) there is nothig more signatures. pictures:
If there's a stamp a 3 o' clock, it's an original Giant Beat.
I asked Paiste, and they also said it's a GB from 1973.
How much can it worth, then?