If the bushing didn't come pre-impregnated with the lube, it can't be added later, although the joint can be maybe be "greased." Not to worry too much about that, since the bronze itself is fairly "lubricious" in contact with an iron/steel bolt/shaft.

If the bushing wasn't prelubed, it could be a fair idea to have someone climb up and slop some grease on occasionally; but I wouldn't see this as a necessary activity. It would be a good notion - just as routine maintainance - to have someone do at least a "visual" on the condition of the whole bell on maybe an annual basis - at the same time that they check for loose shingles and such. If they're so inclined they could take an oilcan up and give it a squirt or two. Common auto engine oil (30W or so) or gear oil (90W?) would probably be as good as anything.

If you have to add a lube after the fact, an automotive chassis grease (Lithium base probably) would be a fair choice for an intitial slobber when the bell goes up, since it's made to get into the cracks and is intended to work in low speed joints and to stay in place.

I'd be inclined to trust the guy that picked the bushing. He may have "lubed" it when he installed it, but if he didn't it probably doesn't need it - or he would have told you what to do.

The replacement of the bolt, incidentally, was probably a wise choice. The durability of a low speed bushed bearing depends on both parts, journal and shaft, being round and well matched in size. The old bolt can be "archived" as a paperweight in the display case where the relics are kept - properly labelled for future generations and entered into the archive documents, of course.

John