If the Exterminator is the plane I'm thinking of, my old buddy from Dayton, Gil Reedy, was flying those when we met. They had two identical motor mounts that were thinned and extended to the tail. The mounts clamped on top and bottom of the wing by two through bolts, one for the bellcrank, and the motor mount holes and then pinched at the tail to form hold a mount for the stab, also bolted in place. They were kinda small, heavy and didn't turn well. He switched to bigger foam planes the year after we met.
A kit in good condition might interest a collector, but probably not anyone interested in building it.