Originally Posted by qc1500
But must the vin be found at the frame too?
No, not unless you question the validity of the number on your tile or plaque or the plaque is missing and the DMV requires that you prove the title matches the trailer. We went for years not knowing our VIN was on the tongue - it wasn't until I stripped the paint & repainted it this past fall that I discovered the VIN was stamped there too.
The number you found may be the patent number for the tongue/hitch coupler.