So for some reason, I haven’t seen any notifications on this thread. I thank everyone for the input that I never saw!
The knees are All-Star XLs (17.5), so that is why they have the extra shield and axis. They’re actually replacements for another set that tore under warranty. They are a year old and are on their last legs (pun not intended), and his replacements were still in production.
But for a fix, I came across a bag of snap screws that I ordered for his helmet a while back. Worked like a charm!