The info you are after should be on the title and/or registration papers. The seller does have clear title and the boat is legally registered in your state - right?
Previously assigned to classic boats, robt smith, one south roselle road, roselle, il, 60172, (312) 894-0900, mso chi, types 13 & 11, inbus 721107 oob 890211.
Blackwell used this mic from 1989 without authorization & built 30 - 40 boats until 000908 when they were assigned the mic.