Help in confirming the authenticity of a Chevy 12 bolt differential

[keith4909]

Looking to buy this differential for my 1967 Gto and I am about 90% sure it's a Chevy 12 bolt from a 1965 chevelle. The diff cover has that little wave indentation in the cover. Can someone confirm asap. Going to pay for it and have it shipped tomorrow and I don't want to buy it if it's an Oldsmobile diff. Thank you

[MonzaRacer]

12 bolts in Pontiacs came same as this, springs held on with bolt on spring cup. Chevys had the punched nipple that centers the springs.
The hardest thing to tell is the fact it has an aluminum rear cover. Look for casting numbers and goolge them. Looks good so far. Width is also a true measure of weather its 64-67 over 68 up axle.
Had one of these in my 70 Monte, 3.55 limited slip.

[keith4909]

From disc to disc is 60.5 inches. The rear cover has the little swerve in it. I had since bought it and it looks great. Thank you for the help