I'll check, but I'm pretty sure a metric wrench fits...(11mm if memory serves...)
If I had more time, I would agree that this would be the best route. They are expensive....If they are a perfect fit though, I will be happy with the money spent knowing they are safer.
Based on how hard they were to find, and my time frame, I might just order what I need, then sort it out later (sell online, probably). If nothing else, we'll have a data point here

As a backup, a gentleman named Sal Walter makes a lot of small parts with oilite and I may or may not have convinced him to speed up development of a bushing/bolt combo as a replacement. I'm trying to keep the jeep as close to current condition, so I'll do my best to keep stock parts, but if all else fails, I'll have to make a choice for safety above looks.
UPDATE: I called the supplier to let him know. He says the issue is with how far into the bolt the grease channel/zerk fitting was drilled. He's sending me a new set of 4 with the correct tolerances. They've removed all the old ones from their stock. I still don't trust the bolts that'll be coming, and I've already ordered the NOS GPW/MB set. So, we'll see what we get when they get here. I'll be sure to measure the tolerances of old/new/nos/replacements and post it all here for comparison.
Cheers!