I went to a local pawn shop this afternoon and found this like new 2240. I put in a CO2 and it works. The Gamo Blue Bomber pellets were included with a previously purchased gun.
They were close at hand so that's what I shot today. Judging from the serial number I think it was mfd in 1987. Tomorrow I plan to shoot it from a rest and try a couple different pellets to see what it likes.