Glock produced this handy graphic to remind you how to lube your Glock handgun and that Glocks do in fact need lube on occasion. Interestingly, the graphic does not list the barrel lugs as a lubrication point which I believe has been mentioned in Glock literature in the past.
I think I over lube all my firearms. Living in Florida makes me paranoid of rust.
I was always taught to lube the bbl lugs as well.