Seth,
I have had two kayaks quite similar to this one. My first one, which I still have, was homemade and I have always guessed the guys who made it did so by using an old Prijon as a pattern for their mold. Mine is made using Kevlar cloth.
Later on, I was given another one that was all fiberglass, and still had the Prijon stickers on it, however it was pretty ragged out, and the fiberglass pretty brittle so I never did anything with it.
I just loved my boat and over the years got much better with it. I thought it carved pretty well but due to it's long, narrow shape I really had to pay attention and lean it enough that my upstream side didn't get grabbed, I took many swims

I must say this was a good design when attaining rapids.
There are a couple of safety issues on these older boats that have been largely addressed with the designs and materials of our newer boats. First is the size and shape of the cockpit. The older boats like mine had a small 'teardrop'
cockpit, whereas the newer boats went to the larger 'keyhole' cockpits years ago. With these older, smaller cockpits it is more critical to be well practiced with your wet exit procedure! Secondly, if the older boats had any kind of bulkheads in the bow and stern, they were usually made from Ethafoam which wasn't as resilient as our more modern Minicell. Often these older foam bulkheads would dry out, shrink, fall out, or get out of position.
Overall, I think these boats can still be great fun to use on occasion, are historically important, and are a great conversation piece. I will always hang on to mine, I have it hanging in the garage like a piece of pre-Columbian artwork
I sure used mine enough that I had to do quite a bit of repair work on it over the years. Like other learning curves, I got better at the repair work too. It was a great help when I found RAKA marine supplier for my cloth and epoxies.
If you buy this boat, keep us informed and shoot some pictures.
Best Regards
Jim