Just to be pedantic, I feel I should mention that .45 GAP is a cartridge, not a firearm. I don't believe Glock or any other firearm manufacturer sells a pistol called a "GAP." Is it safe to assume that you're really asking who has fired Glock's .45 GAP model, or are you asking about firing any make or model that's chambered for .45 GAP?
Yes, you are correct, but since the .45GAP cartridge is almost totally only used in Glock models G37, G38 and G39 (Gen 3 and hopefully someday Gen 4), the two (cartridge and handgun model) have become synonymous in common parlance. However, I apologize for any confusion I may have caused.