The question is, are these UDIDs real? If so, then where did AntiSec get them from if not a compromised FBI laptop? If they'd hacked Apple or a carrier, surely they'd be quite as happy to crow about that as anything else.
I can understand the idea of pinning the leak on the FBI, I'm just unsure as to how plausible that is. They and their contractors have shown themselves leaky enough to not need any fabrication of evidence in the pursuit of lulz.