Should I replace this cardboard insulator in my range terminal block box? (And if so, what with?)

A loose connection, or undersized wiring, (or both), caused overheating/arcing in my range terminal block box. I’m in the process of correcting the wire size and replacing the terminal block, but I wasn’t sure what to do about this cardboard insulating piece that sat behind the terminal block. It’s scorched, but not burned all the way through. Should I replace it to be safe, and if so, what with?