Ideas on the price I should pay for custom M21...

The gun is 1 of only 2 like it. They were ordered specifically built by a friend of mine. Heat treated stainless full auto receivers (but in semi auto) super match grade stainless barrles, adjustable stock, 2 point scope mounts,match trigger groups, match suppressors, bushings.buffers etc. We called to see about having another one built and the head armorer said he couldn't even get that grade of metal any more. He offered 2 times what the original price paid was, to buy them back for his self. Not even 200rnds through it.