Yes- - -my 59 3800 came to me with one flywheel bolt missing, and a massive oil leak that ruined the clutch. The PO who "rebuilt" it before he sold it to me cross-threaded a flywheel bolt and then left it out. A star washer or a split lock washer would be a bad idea.

Loctite on the threads also makes a good oil seal.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!