Should I proactively replace my Federal Pacific service disconnect boxes? (not a breaker panel)
No you do not need to replace them, their disconnects are fine and also their transformers are good. FPE stablock is what gave them a bad name. It would be like saying your favorite car MFG was judged by that 1 bad model (they all have them). I have several that have been in regular use for decades, so would not worry about the disconnects.