When my BBB's were sent off to be powder coated, the person who coated them didn't even take them apart. There was over-spray on the exposed shaft so I took them apart and had a local company strip and recoat just the housings. I even found the rubber seals were pretty much fried and found some replacements.
When I was putting them back togther, I had some Loc-Tite run down one of the shafts. As soon as I realized this, I scrambled to take it apart and cleaned it all up again. I was more careful the second time. If you rebuild them, I would suggest new screws and use just a little bit of Loc-Tite. You could even flatten the end of the screw after it is completely screwed in to ensure the screws don't come loose. I also pus some lubricant on the shafts and they open and close buttery smooth (even still).