Given it's a GSA, it's MS. And, given the scuffs and nicks, but fairly clean fields, I'm in the "62 with a possibility at 63" camp. Nice coin! I like GSAs. Had one that I paid MS-62 money for, which ended up grading NGC MS-65, that I now wish I had kept. Might have to search for another like that.
GSA called “Uncirculated” back in the day. I would market grade it as an MS-62. Some will say AU-58 because of the break in the frost. No all GSA coins had the “Uncirculated” label. If that spot on the GSA holder is blank, the graders thought it was something less. Some of those coins really are Mint State.
I'd go ms61 to 62. Nice coin, especially considering it's right at the start of the series and has a few decades on younger examples.