This is correct. If you Google Apple patents, you'll notice that Apple patents & trademarks EVERYTHING they make. For example, they have a patent on the screen protector for an iPhone 4s. That means if Belkin or another manufacturer of screen protectors wants to make them for the 4s, they have to have a licensing agreement (and shell out some $$$) to make them legally.
Needless to say, plenty of illegal things happen in the US, and other countries. I just brought up the issue because it was a pretty serious show of force from the US DoHS, and even more serious that there are entire businesses that depend on these repairs and products to exist.
After speaking with several attorneys, it seems like the possession of these items IS, in fact, ILLEGAL. Thus performing the repairs is impossible.
Apple does not have a Reseller or Authorized Service Center program for the US, nor does it certify anyone to sell Apple parts. Thus, no such thing as "Apple Aftermarket Parts" - that seems to be the current loophole, although really it means nothing if they come to raid you. Counterfeit is Counterfeit, and that's the law.
(that being said, it's pretty ****** that we have this going on, while having a ridiculous amount of REAL issues to deal with in the US, especially related to Homeland Security)