[Chuck Schwark]

No, usually not, as they are specific values for tuning and other RF/IF tuned applications. Micas rarely go bad. Changing these may make subsequent re-alignment impossible or troublesome if not changed out with the exact capacitance values in the schematic or parts listing.

I'd leave them be.

Off-value resistors, wax-paper and electrolytic caps are 99% of the problems with a typical radio, aside from other problems like open coils, fried parts, bad tubes, previously attempted "repairs", etc.

Chuck