Trailer manufacturer id number, need vin?

[FULL-THROTTLE]

I just found the trailers manufacturers 5 digit id number, how can I cross reference this to a vin? I have no paperwork except a bill of sale with no vin listed and the vin is long gone from the trailer

[Blackntan90]

I was able to get my trailer VIN from the motor vehicle department in MD. The first owner actually lived in Delaware.