Buy boat, no hull#??

[massnspace]

Looking at a sailboat to possibly purchase. 1980.

Owner has clear title, I have seen it, but there is NO hull number on the transom. Transom has been painted, so maybe it was filled in and painted over????

Any ideas? Is it a big deal?

[Tin Tin]

So what numbers are on the paperwork - a HIN, a USCG ID, a state registration number, engine serial number?