How can you tell from that stamp that the cymbal is from the 60's? My cymbals are from the 70's but the stamp appears to be the same.
I'm not sure how deep your question goes. Have you read up on the differences which Bill Hartrick (Drumaholic) originally documented? If not then you might want to jump into the middle of things and just start here:
http://black.net.nz/avedis/avedis-gallery.html#60s
In the strictest interpretation, the stamped in trademark which appears on a cymbal tells you which stamp was applied to it rather than precisely what year it was manufactured.
There are plenty of cymbals which have production clues (hammering style and lathing style and bell morphology) from one era and a trademark die stamp from a later era.
Cymbals were hammered and lathed and then left to rest in the vault, sometimes for 7 or more years. When they were picked by testers to fill an order then they received ink stamps and the die stamped trademark was pressed in. At least that's what Leon Chiappini says about the process, and he was in charge.
But we tend to drop all those distinctions and just say "that's a 60s cymbal" when it has a 60s stamp. And yes, the die stamp on the 26" appears to be a 60s stamp (answering the original question). However, I still can't rule out Bill Hartrick identifying it as a 1954 stamp because I don't know what he looks for to uniquely identify a 1954 stamp from the die stamp alone:
http://www.vintagedrumforum.com/showthread.php?t=16096&highlight=1954
If you show us a photo of your cymbal we can comment on it. Other than that, it's hard to say whether you are seeing all the distinctions I've tried to document which contrast different production eras. You also need to remember that you may have purchased brand new cymbals in a retail shop in the late 1970s which were manufactured in the early 1960s but were in the supply line in the intervening years.
The current record for number of years in the supply line goes to a late 1930s/early 40s cymbal purchased new in the 1970s. That's 3 decades in the supply line: