Yeah, that GC is a hollow logo era match (1978-1982 or so). You will normally find these with a 70's stamp (no 3 dots). But probably will find them with an 80's stamp as well (big CO with 3 dots). They could be any combo of those....though it would be more likely to have both 70's stamps or both 80's stamps. And you would want the bottom hat to say "bottom new beat hi hat." The weight spread on these can be anything from 250-500 gms. Ensure you get a spread you actually might like and can play. You can probably get GC to weigh it. For yours I'd try to find a bottom in the 1300-1400 gm range. Heavy bottoms are not hard to find. I have a mid-80's pair with solid logos - 1025/1360.
Believe it or not I've been playing drums for 30 years and these are only the second pair of new beats I've owned. Had a set of 90's ones that were too heavy and flipped them quickly. Always played 602's and 2002's . What kind of spread do you guys usually go for with these? Is there any benefit to cleaning just the bottom or just the top? Mine are both filthy but I kind of like how they sound. Might just keep the 1244 gram 60's bottom? Haven't played them live with a band yet which is the real test.
I clean the tops because I like the bling! I'm a fan of the 60's tall stamp hat bottoms....to me they sizzle better than the 70's. and that 1244 weight sounds ideal. At one point you may want to try a thinner top around 900g just for comparison.
Zenstat and others have discussed the spreads before. 750-850 / 1050-1200 is a pretty cool and versatile spread for anything from jazz to rock. I prefer 800-825 / 1100-1175. Enough wash with plenty of articulation and cut. For progressive/rock/fusion then the 1000-1100/1250-1350 can work well. Sabians often run around 900-1000/1400-1550 - 500 gm spreads! Those must really cut. Tried some early 602's that had a 100 gm spread or so....and they didn't give me anything the matched for new beat Zildjians couldn't provide. Currently using 4 pairs of Zildjians: early 70's 14 new beats 815/1145, late 50's 14 Zildjians 735/755, Trans stamp 15 Zildjians 840/895, and a 50's/60's pair of 15's 890/1000. They all do something a little different. Out of the 4....the early 70's New Beats I bought new are the most versatile and can handle most anything.
I usually prefer mine untoned to make them a little darker, dryer....more a vintage feel. But if I vintage pair that's barely toned, I won't 'dirty' them up. They'll do fine.