Clymer is a good manual... one of the best but it should be borne in mind that it was written and published 45 years ago in the 1970s when these bikes were still relatively new. They were advising on rebuilding new bikes
The way I viewed this when I rebuilt my 79 engine was this .
The engine is nearly 40 years old ......
I have no idea of its history for the past 40 years.
It could have been raced, seized, abused, over torqued, not maintained properly, distorted due to excessive heat etc etc
We have a choice . To get an engineering shop to resurface the cylinder , barrels, head, crankcase etc so that all mating surfaces are true and correctly aligned.(expensive)
Or apply some liquid gasket to both mating surfaces in addition to the gasket. (very cheap )
The way I see it liquid gasket cannot cause any sealing problems but it well prevent them and it is a belt-and-braces approach to achieving a 100% seal wheras using a modern, often poor quality gasket on its own with mating surfaces that have not been skimmed and aligned..... well its asking for problems in my opinion.
If leaks occur .............then the engine gets torqued and retorqued to within an inch of its life at higher and higher torque in an attempt to stop the leak resulting distorted bolts and crankcase thread damage.