Or...don't buy a gasket, lay the bike on its side (so you don't have to drain the oil) and then take the cover off to find exactly what J-Who says to look for.
Does this bike have multiple covers on the RH side? You may end up having to take off more than the clutch access cover to really see what's going on. That means taking the kicker off? That might be kind of stuck.
Heck, it won't leak (much) when you put it back together with a bit of RTV or somesuch. Well, mine doesn't and I've had that cover off 1/2 dozen times and haven't changed the gasket yet.
No, I don't have an '84.
This is a not uncommon problem with 'H' models, though.