If the VIN is attatched to the dash, and it is advertised as a part of the sale, it is illigeal. If it is never mentioned, nor shown, then it is a discretionary thing. i can understand that maybe the seller does not want to risk drilling it out if it's a good dash, but... (I don't condone it at all regardless) Selling VINS is illigal in most states. As Barry says, know the laws in your state before you purchase.
Yeah, I like the guy who asks about the cowl stamp and fender tag and rad support. Then the seller pies in with a HF letter stamping kit. Now that is one for the books.....
Dan