I don't really know.. but at first glance the hubs look like a Coleman hub, so could be that?

Not all Rockwell axles are top loaders, I have seen many Rockwell front axles like yours, not counting the hubs though.

Is there a tag on the inside of the glove box door? if so it should tell you lots if info about the different components of the drive-train.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-