DANA 44 ID help needed

[Americanrider]

I'm going ahead with the Dana 44 swap in my 67 K20. Between drum brakes pulling to one side and a leaky knuckle seal I have had enough, also I'll be jumping into a higher gear range for better mileage. I came across a GM Dana 44 donor 8 lug axle for a resonable amount. The only problem is that the PO doesn't remember what year it came out of. After researching on the web I can't find any Spicer BOM numbers that match the ones on the axle. I've even called a few local shops and they called shops in Seattle.... so far Nuttin!
Every Spicer/DANA number listing of BOM [Bill of Material] numbers list only goes as far back as 1979. The Spicer website only goes back to '79 also. If anyone can help ID this I would be thankful, here are the clues:

It has a 4.09 ratio (no tag so I counted the teeth)
The BOM is 603676-1
Date code is 636 5AE
Stamped 44-F8 on the diff
Dust/gravel rotor sheilds are heavy duty (thicker than the 72 axle I have)
The spring pads are the same measurements as mine in the '67

I need to know what bearings & seals as well as a set of re-built calipers to get. I'm in a pinch because I've already sold my 4.55 gearset to board member Gyva over in Idaho. Here is a couple of pics of my donor axle.
Thanks in advance!