What the hell is this rear from?

I am trying to identify what my rear is out of. It is a 12 bolt the number on the p*** side axle tube is 3896839, and GM84 on driver side axle tube. The width is 58" backing plate to backing plate, and has 4 3/4 bolt pattern. I need to order a new posi diff and gears and need to know what rear to order it from.

 

look in a Summit catalog, they have pics of the cover gasket shape for the different styles of rearends.

but it sound like it could be a 65-70 Chevy full size car 12 bolt, if it has 12 bolts holding the ring gear to the diff housing. The ring gear outside diameter would be 8.875". Also it would have some numbers on the ring gear that might help identify it further, such as ratio and a date code.

 

also look on the axle tube, for a stamped number/letter sequence, "metal stamp on left rear axle tube on rear side, letters and numerals 3/16" high, 3" outboard of carrier"

I have a book that lists the codes for 65-75 chevys

 

right now i have a 68 bel-air wagon with that same 12 bolt rear in it same bolt pattern too

 

I can't find a letter and number sequence on axle tube, but it has been ground down and welded for new perches, so it may have been removed or covered. Looks like it had brackets for trailing arms at one time, now leaf spring under my 50 chevy truck. I suppose I will just have to remove the cover and see whats inside before I order the new parts, it's just a pain because it is my only transportation right now.

 

HI trying to figure out my axle code it reads HE5 0 3W....any info would be great thanks