I am currently selling my 10 bolt that i pulled out of my 1968 gto. However, when measuring the flange-to-flange measurement, it comes out to 56.5 inches. That's the measurement for a 64-67 a-body rearend. (68-72 should be 58.5).
THIS MEANS THAT MY REAREND IS A 64-67 REAREND RIGHT?

However, there's a date code that says D169
D=April
16= (april) 16th
9= 1969.....???

if the date code says 1969, why is the flange-to-flange measurement 56.5 inches??

However when I did some research, I came across this on multiple websites:

"1967 was a transition year in which A-cars might have a 1964-66 style rearend, a 1968-72 rearend (which is wider, and commonly available), or a "hybrid" rearend, which will have the 58.5" width"

i have a 1968 gto THAT WAS SOLD IN DECEMBER OF 1967 (an early bird). So it was built in 1967.

im so confused right now as to what rearend i have, as the only codes i can come across are:

D169
979?08
the letter N
and no sign of an 8 digit+ # (ex: 3894938N) and no code on the tubes (this rearend is badly degraded and covered in grease-mud)