Yes but it will be slightly narrower wheel-to-wheel(1/2" per side) but that may work in his favor.
Lower coil spring perch is different, but the adapter retainer parts are available low cost or he can just get new springs if his old 72's are shot anyway.
Maybe?? some difference at the u-joint yoke, i don't recall. But it can be dealt with.
I thought the '71 Skylark was in that class of first to use the new corporate 8.5" 10-bolt??....he better check, I wouldn't want to give that up for an 8.2" swap unless it was just a temporary swap. Hang on to that 8.5" and don't junk it if it has one, save it aside.