Are UPC codes required for FBM?

I’ve already established my brand and have been selling on another platform for over a year and a half. I’m getting ready to start selling my products on Amazon. I’m going to start with FBM to test the waters. I’ve tried looking for the answer to my question and have gotten mixed results. I know I’ll need a UPC code for each product if I start doing FBA. Do I still need a UPC code even if I’m doing FBM? TIA