Hello Eric
I have a 1989 Parker 27, so a slightly later version of your Super Seal.
When I was in the process of buying her, and afterwards too, I searched high and low inside and outside of the transom for any sign of the HIN, but without success.
Before the EU Recreational Craft Directive came into law on 16th June 1998, there was no legal requirement in the UK for any boat builder to actually mark or record any HIN at all. Most volume builders did do so in some way or other, but each had their own system. Often this was displayed on the transom, in the cockpit but sometimes just on a plate within the cabin. And a plate could all too easily be removed by a sentimental owner when he came to sell the boat ...
I'll "watch" this topic in case someone else can enlighten both of us!
sincerely
Geoff
Geoff Sheddick
Parker 27/146 "Stroller'