Have a Glock 22 with S/N starting with ABUXXX (april 1992). I bought it new after coming home from Desert Storm while in the Marines. At one point I drilled two holes in the frame in front of the trigger guard to mount a bracket for a red dot scope mount. No finger grooves on the grip. I have always used Hogue grip. Been thinking of upgrading frame through Glock. They said they would do the frame, refinish slide, replace sights, all springs, new mag springs for $200. I'm not sure if that is upgrade to Gen3 or Gen4. Catch is, the new frame would not have same ABU s/n. The barrel and frame would mismatch s/n's. Is my G22 old enough to have any "extra" future value? If they are all the same, why not upgrade to "mostly" new for 2/5ths price?