Some excellent guesses. 2rocky you're pretty good. I couldn't find the original sheet, but he grossed 79 6/8 with 2 inches of deductions. I rescored him quick to get the specifics and came to 76 7/8 instead of 77 6/8 net. I'm sure the difference is in shrinkage of the d1 and d2.
Horn length: 13 4/8
D1: 6 6/8
D2: 6 7/8
D3: 4 0
D4: 2 7/8
Prong: 5 2/8
I'm sure the discrepancy over the years was shrinkage in the first two circumferences. I remember him being over 7 for all four of those originally. He's just euroed and the sheaths aren't secured to the cores to prevent them from shrinking.
This buck is a good example that horn length is a small part of the score.