Iron Horse, good idea drilling the pin lengthwise and crosswise. The pin in the second pix with the center section expose, I'd make a sleeve of maybe water pipe, that would fit pretty tight lengthwise and drill it in center and put in a zerk fitting. If it fits pretty snug grease will probably be forced along the rest of the pin. Grease would be better than oil and it will also flush any grit, sand out and help prevent the pin from being ground away slowly. I'm sure these are hardened pins also. The grease fitting in the cylinder end is there to grease the cylinder bushing and will also grease the pin.
You might check with a few dealers and find pins with the same diameter etc WITH GREASE FITTINGS.
My question as I am not familar with these tractors....... are the bushings for these pins replaceable????? Just wondering. I worked on a lot of industrial equipment over the years and figure they are possibly replaceable.
I will try to find manual on tractors and see what I can come up with.