It’s definitely a lube screw. My
P2009’s head started rattling. Took screw out pumped some grease in . Good for now . I saw grease had come out around where head mounts. I can’t find info on what grease is used or how often . So seal must weep out grease till bearings fail. Too much grease creates heat and will cause seal to fail . It’s a pain to deal with at one year old. A better seal would fix .