[Raleigh]

Voltage ratings of caps depend on their function. I don't know which caps you are talking about, but caps that handle audio frequencies in the final output stages often have high voltage ratings because of high voltage AC transients, not because of the DC voltage. I'd use the same voltage ratings as the originals.

Maybe others can comment about this specific radio and about these specific capacitors, or if modern capacitors are capable of handling transients better than the old ones did. 2000 v sounds very high, but 1000 to 1600 volts is kind of typical for some output stage capacitors.