Even without a grease cup, there needs to be a spring and a phenolic disc riding against the shaft inside that hole. You can install a 1/8" pipe thread grease fitting and give it a very small shot of grease at every tuneup if you desire.
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!