1. Steering damper, bolts onto rack. G40/GT specific.
2. Clocks, G40 specific
3. Lower arms on front have a rose joint on the chassis end, G40 specific
4. Engine bay loom (worth getting the lot, including the annoying to remove fuse box and connections that pass through the bulkhead). Engine bay loom is G40 specific.
5. Lambda, G40 specific
6. Rear beam has ARB in it, GT/G40 specific
7. G40 badge (grille, rear hatch) "supercharged" badge (rear hatch if fitted), G40 specific.
8. Engine mounts, certainly charger mount is G40 specific, unsure on other two. Worth getting though.
9. 5th gear linkage, not G40 specific, but if you end up with a 4spd shell you'll need this bit to convert to 5spd.
10. Steering wheel, usually something special, have it away with you!
To be honest, I reckon you could strip it to a bare shell if you go for it, definitely take a couple of cans of release spray (also a can of freeze spray for super tough rusted bits, makes the rust disintegrate rather than soaking in and turning it to mush like release spray). I've done a few myself previously, I shake my head at some of the decent shells I've cut up previously
"That's the way she goes" though.
Don't worry baout pulling everything apart, just pull the major bits off then work onto the smaller bits, you can spend ages trying unstick things, spray them with lube and come back to it after you've done the rest.