I'm prepared to give the benifit of the doubt either way, but like I sid there are some things I'd like to see in person, or have someone to see in person to be sure. Just because it is described as "original and unrestored" doesn't mean it didn't have some touching up, possibly even major touching up, in the Navy. Just looking at the pictures Russell posted of the 64's, I see one with a cranked-up bumper that looks like it was towed wrong by the motor pool. It could have been repainted in part or in whole, but the VIN tag is odd to me. I can see there being screws if it was repainted and they wanted to not paint the VIN tag, or I can see the tag being painted over and remain riveted on, but why both?
If it was sold at government auction that would explain the difference in number sizes, since they were probably removed for auction, but it would also imply that someone somewhere along the line knew what they had and restored it accordingly, so it seems odd that word would only come out now?
The Navy ID plate lists an "Engine Serial Number" which is the same, at least in part, as the VIN tag. If the car is indeed original and never had the engine out or worked on, this number SHOULD still be stamped into the engine block, although certain circumstances might preclude it from being there. This could be faked too (anything can, really) but it would help the case if it were there. Same story for the frame serial number.
If this is Bobb Kosoff's car redone it doesn't necessarily mean it is a fake, just that there may be more proof now that it is the real thing. As I understand it, he thought his car was the "real" one for a while, then apparently admitted at some point it was "a really good clone". It's possible that enough people put doubt in his mind that he unconvinced himself that his car was the real one, sold it, and now under closer examination it turns out it is indeed the real one? That's if this is even the same car, which no one on this board is sure of. I don't know, just thinking out loud to stimulate discussion...