Grease zerks/fittings..........

[LOUD MOUSE]

The hole does give access to the area where ya add grease but I've never seen a special tool/yip for it.
If ya have one of those pointed grease fittings that fits the gun ya can get grease in there. ............lm

No resolve on this one, I did install the correct screw in there though. I suppose you still could screw in a grease fitting, but the threads may be an issue.