TOPIC: I.D. on a late 50's Gator?

I bought a '59 boat on a '57 Gator trailer, but the seller of the rig to me had the trailer i.d.'ed as a 1988 Cox. They are like apples and oranges, no way do they even look the same. I'm trying to get DMV to change the registration, but they want a proof of i.d. on the trailer. Any idea where Gator did this? I can't find anything on it, though it was obviously repainted at some point.

Any help greatly appreciated.

Frank