Nice!
I see that some of these Hogs have the 'Batelle Device' (Gun Gas Diverter) fitted to the gun muzzles. This was a short lived contraption that was designed to divert the gun gasses away from being ingested by the engines.
The device never really worked very well, and many aircraft did suffer excessive vibrations caused by the gun gas diverters. Some even had cracks appear in the aircraft nose as a result

. Probably the reason why they were short lived?
TankBuster