Notes I got this from saberjunky, who in turn won it at auction at the Master Replicas Collectors Society Party at Jim Henson Studios back during Celebration IV.
Notes The blaster is technically not the Prototype of the ANH, but is one of the Prototypes of the ESB variant which was built up on one of the ANH blasters. I picked this up from Steve Dymszo directly, who said it was one of four produced, that the design had been approved but just never made it into production.
Notes Got this from Steve D.; it is one of the two original prototypes, the other having been sent to Hong Kong. It is actually a plastic shell, rather then the diecast zamac that was used for the version mass produced by MR.