Any numbers cast or stamped into the diff housing or on the axle tubes? 4.11 gears aren't real rare, could be from just about anything and I believe the ring & pinions weren't specific to a year/model. If those numbers are all you can find you could try contacting a rear end shop in your area and see what they have for references.

1956 GMC 370 dump " 'Tater "
1970 VW Volksrod "the Black Bomber"
2007 Chevy Avalanche
2020 Jeep Cherokee Trailhawk,
2005 Harley Davidson FLHTCUI

I dig all cars, old and new, whether they were hammered out of American iron, German steel, or Japanese tin cans. Being unable to appreciate them all is missing out on a world of great things.
But thats just MY opinion! :P