I finally finished both differential fluid changes this weekend following Ken's 1985 Refurb thread.
Sanded and painted the diff covers and replaced the AMC 20 torx bolts worth standard hex bolts. See finished pix!
The only issue I hit was the AMC 20 omix ada gasket I ordered was to big. In my haste, I opted for just using a lot of gallery maker. In retrospect, I should have cut out a section of the cork gasket to make it fit... But oh well. Time will tell if it holds. At least I got that gunky grey gear oil out and saw no issues with the gears!