It appears to be very close. Your full reverse image certainly makes it look like displacement at the left star and below the D. I'm not sure the 6A is a true R6 but the 6B appears to be a true R7 based on the SSDC census. Nice pick!
edit to add - your example is not quite as advanced as the ANACS AU50 example labeled WOW! BOOK PLATE COIN but there's a PCGS AU53 example that if correctly attributed yours surpasses.
Hopefully AU90o chimes in.