It might be easier for to figure out the diameter and lengths needed and just buy some round stock with the proper diameter from McMaster Carr or something similar and cut to whatever length you need. 1045 or 4140 steel will be just fine.
Another option, and probably the best one, is to contact a machinist and see if he can turn a couple pins for you. Doing this way, he can easily drill through the center of the pin for a grease passage and add the grease zerk if that's how that's loader is greased. You'll need to provided the diameter and length needed.