There is a lubrication hole in the hinges, but they probably never got oiled (and the oil can't really get to the upper part of the hinge. The pins tend to seize in the bar and start turning in the outer part, wearing that out. That's the way mine were anyway. I had to get medieval on one or two of them to get the pins out.
A grease zerk is a great idea.

I may have to look into that. I'm not sure there's enough room to clear the hinge body, but I'll definitely check. I still haven't put mine back together yet.