Yes, I would disassemble them all. That is, if I had sets of rails already covered to swap out. Takes 10 minutes to swap out a set if you already have them ready to go. Take the old ones off, pull the Slate, recover it, drop slate back in the position, and bolt on the new rails. Done.
This is naturally assuming we're talkin about vendor tables here. Customer-owned tables will sometimes get a different treatment, because usually they want to keep the same rails they have. Unless they're putting on brand new Penguins or something like that.
And it very well could be they are getting different tables eventually. I was just covering the refurbishing aspect.