I'm guessing the last three digits are "-541" but I can't make out what's before it from the photo.
My own copy purchased in '77 or '78 says 2T-541; however, I don't think mine is a 1st-pressing since it came without a poster.
I'm wondering if yours is an older or newer pressing, or possibly a record club issue with alternate catalog number ?
I appreciate your sharing it (since I'm too lazy to order a new belt for my turntable.)