It depends on how long your state will hold information until the system is purged. They do not hold data indefinitely.
As Darrell mentioned, Tennessee changed a few years back - they stopped going back to the archives (which are on microfiche) due to fewer employees and no overtime, according to the DOT office. They still have the records, but just won't cooperate and look them up. Even when they did, in the last years they would go all the way back, the Federal Privacy Act forbid them to hand out the paperwork with owner's names or personal info on them, so they redacted the names. Thanks goodness I got mine before they clamped down - all the paperwork from new on both the '68 and '69 Z's (they were sold new in Tennessee). Looked up a couple of others over the years as well. A real gift -
Point is, maybe you can negotiate with a willing DOT clerk in your state - I'd bet that most states have archives somewhere; the trick would be to get someone to locate and/or dive in to find them. I wonder if offering to fund some overtime would help motivate some people - just my opinion. How much would it be worth to anyone to own documentation ?
Regards,
Steve