8.75 driver side axle flange is different?

The axle adjuster is supposed to be on the passenger side. They are reversed based on your description and pictures..

Mine was stock on the drivers side from the factory !-1966 belvedere .
If you check my post, I said "supposed" to be on the passenger side. Meaning that there could be other possibilities found.
Hey, I bought a B-Body 8-3/4 axle a few years ago from a friend's estate and I found that there were adjusters on both sides.
I sold it the same way that I found it, but I knew if having two adjuster would create a problem or not.