Thanks for your insight. I appreciate it. I’ll wait until I hear back from the owner. They’ve had the bike for 10 years so hopefully they can provide more info too.I'm pretty certain it isn't a prototype. It's an early Coyote hardtail frame with the rear dropouts cut off and an aftermarket rear suspension added. That could have been undertaken by the original owner or by the Coyote importers (they didn't manufacture anything). The first Coyote full suspension bikes were all manufactured by Fastrax and this doesn't bear any resemblance to those designs.
It is possible that the rear suspension was manufactured by Fastrax, I really don't know. But I'm sure someone on here will recognise it and have more info.
Thanks so far.