I have a Serpa for my G23. I don't have a .22 conversion for it just yet but it looks like if I did, the supp would pass through it with no problem straight in and out.
After thinking about it however, it doesn't seem it would be very practical on a hip holster since it's an extra 6 inches that you would have to draw straight up. Carrying it on the thigh rig seems like it would be more comfortable and convenient but likely opens the door to possibilities of damaging both the suppressor and the gun.