All RB's use the same clutch/flywheel. All RB's use the same bellhousing.
Do the throwout bearing and spigot bush if it makes you feel better, not urgent unless they're f**ked.
Other things you need... Clutch lines, fork, master, pedal.... I'm assuming you probably have a previously auto engine going into a manual shell?
These are the Nissan part #'s for bolts you need, will be about $30 all up.
0112105121 You need 4
3137715U00 You need 3
3137715U01 You need 1
Haven't used a cushion button clutch so can't comment on that.