I know this is a few months after the original post, but I am in the middle of rebuilding my front end. The boots on my CV axles were torn and slinging grease around, although they weren't making any noise. Anyway, I just sent my axles (which were original to the truck) to CV Source, Inc. to be rebuilt/serviced. The owner, Jon, was super cool to deal with, and promptly answered all my questions via email. I wasn't sure if my axles were original or aftermarket (they can't rebuild aftermarket, a/k/a Chineseium ones), so I sent him pictures, and he confirmed they were the originals. Weighing in at 50 pounds, they weren't cheap to ship (I live about 900 miles north of Georgia, where CV Source is located), so I wanted to make sure they were originals.
I packaged them with plenty of cardboard padding, and received them back in just seven days, so turnaround time is very good. Paid over the phone with a credit card.
Jon said the aftermarket axles, besides being non-rebuildable, are not as heavily built. He said if you hit the aftermarket axles with even a light hammer blow, it will leave a dent mark, whereas it won't make a dent in the OEM axles.
-Ken