Just have a few that are true prototypes. Usually they fall into one of two categories: either an in-house test, or an athlete sample.
My hand painted Flying Tiger Oil Rig is a test of the color scheme, which later was used on the Gascan. There's also a Yellow hand painted Gascan, and two blue Hijinx.
These two are athlete samples. Usually identical to production models, but with varying color schemes.
This might also fall under the same category, but I don't know the details.
This was one of 7 used to test the interest in flame patterns. A normal black pair was airbrushed and sold at the Irvine Spectrum store. After that, the flame pattern became a print.
And I still have no idea, nor any records of the Purple Cloud Frogskin. However the Bronze lens matches the options at the time.