As I've disassembled everything and prepared to put it all back together I was perusing this page at Cruiser Outfitters and noticed that my differential flanges aren't stock.
Cruiser Outfitters
Seems someone replaced the stock 3.7 diffs with 4.11s. The transfer case remains stock with 19 spline outputs. (Also based on this page:
Cruiser Outfitters).
Thanks to Kurt and Bryce at Cruiser Outfitters for answering my emails and phone call wondering what if anything I should do. I do not intend to do heavy offroading with this, only things I can make it back from.

So keeping it as-is and not going back to fine splines. Plus, all the internals look great. My main concern was that finding this change would cause problems with the ARB rear locker I purchased, but it doesn't.
Also:
About to ship a load of hardware off for plating.
Picking up a dial indicator setup for the diff work I'm about to start.
Finishing a smaller painting booth so that my barn-age remains usable even if I'm treating and painting parts.