Need help pricing a stolen G&L prototype

Hey, gang.

I need to come up with a market value estimate for my insurance company. My G&L prototype, circa 1986, was stolen from my recording studio in South Austin last month. After combing the pawn shops, eBay, and craigslist, I've finally resorted to filing a claim.
It was purchased in Dallas back around 1986. Somehow, this little music shop in Prestonwood Mall got a hold of a number of G&L prototypes. I think that the one I purchased was what later became the Invader, but I could be wrong. I paid around $1000 for it at the time. It has a natural finish; no name, just "G&L" on the headstock; Kahler Tremelo; no pick guard; two single coils and a humbucker, each with it's own on/off switch.

Anyway, I'm hoping I can get some advice from you more knowledgeable guitar aficionados on what the market value may be.

Thanks so much for any input.

My hunch is that the insurance company will only give you the replacement cost of an Invader of the same vintage, more or less. The Invader came out mid-80s so I think they'll just go with that info unless you have documentation that it was a prototype per se and that the documentation can be appraised.

Anyway, wish I could be more help .... sorry for the loss and I hope it works out.

Thanks for the reply. For some reason, they are asking me to come up with a price for it, but I'm sure they'll need to verify it somehow. Unfortunately, all the documentation burned up in an apartment fire back in 1989. Fortunately, I was at band practice when the fire started, so I had the guitar with me. I sure miss it now, though. I see someone is selling a double neck prototype on eBay from the same time period... too rich for my blood, though.

Earlier this year, a 1984 prototype of the Skyhawk designed by Leo Fender and George Fullerton (but with a factory synth) went for $2500 on an online auction.