ALICE frame and straps change from LC-1 to LC-2
LC 1 frame, notice the much thinner waist strap and smaller kidney pad
LC 2 frame, notice the quick release thicker waist strap and larger, thicker kidney pad
Additional Makita Battery and housing added to GB2 packs. These were used to power the circuits.
All these differences are marginal, if you wish to go all out on a particular style pack, feel free to, though if you wish to pick elements of which pack you like, that is perfectly acceptable too. Many builders find getting certain parts quite difficult. Remember, a lot of these parts are vintage now, so they’re only become more scarce. Picking elements from ghostbusters 1 and 2 for your pack build is absolutely fine.