There were many legendary Boston Celtics championship teams, but what is unique about this special signed basketball is that it was signed at the time in 1964-65, not at a reunion years later of a title team.
The unique Rawlings roundball is inked by the Celtics team members, highlighted by icons Bill Russell, Coach Red Auerbach, Tom Heinsohn, Sam Jones, John Havlicek and K.C. Jones. Another unique aspect of the '64-65 roster is that John Thompson was a backup center for the Celts, years before his ascent as a legendary Hall of Fame Coach at Georgetown University.
Others that have signed the ball are Willie Naulls, Tom Sanders, Larry Siegfried, Ron Bonham, Mel Counts, Trainer Buddy LeRoux.
The signatures have some fading but all are legible, grading 3-4/10 except for Counts (barely visible). You can tell that autographs were signed with purpose and care at the time.
Beckett has examined the basketball and provided the LOA.