If the generator has ever been rebuilt, there's a good possibility that the original open bearings have been replaced with sealed ones. That makes those lube cups nothing but cosmetic decorations. Some low output generators used a bronze bushing at the rear, which needs an occasional shot of oil in the cup.
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!