There’s some subtle differences between the packs from ghostbusters 1 and 2. Most noticeably, the ribbon cable changes from the first film, which was from the wiring for a light aircraft landing gear to a off the shelf strip of fine wire ribbon cable.
Ghostbusters
Ghostbusters II
The angle of the thrower on the V hook also changed from the first and second film. This was to allow the actors to grab and un-holster the thrower much easier.
A Ghostbusters II angled vhook
The crank knob on the gearbox changes colour from grey to black.
Ghostbusters
Ghostbusters II
The clippard fitting on the ion arm goes from a square fitting that’s mounted on the ion arm cap to a hexagonal fitting that sits just after the cap.
Dale resistors on the ion arm also change, gb1 having horizontal ribbing, gb2 having vertical.