I'm really picking up an undercurrent of "Steve Wozniak being who he is in relation to Apple, this joke probably means that Apple has gotten over it". I don't see the evidence to back that argument up.
I think the simple fact that Wozniak (who as far as I know is one of the nicest really rich people out there, by his deeds, not by his words) is willing to do this in a way suggests that it could have happened to anybody. Shit happens, prototypes get lost.
Stuff happens to prototypes quite frequently, especially car prototypes that suddenly and unexpectedly highlight both the existence of the prototype and the unfortunate person in possession of it, you can't have the one without the other.
Keep in mind that it wasn't Wozniak that released Grays name, effectively he's saying it could have been him, since he goes out drinking as well.
Maybe I'm giving Wozniak too much credit based on his past, but I can't imagine him doing this out of malice.
Surely that's the surface rathrr than the subtext of my commemt :) But yeah, it is only a qualified guess on my part, as Wozniak is not known for vindictive behavior.