...so caps be .01 .05 so on 450v to 600v ...
These days you are more likely to find 0.047 uF (or 47 nF)
instead of 0.05 uF, due to the change to standard values.
Don't worry, it should work just as well. Smaller values
are likely to be nF or pF, instead of mickey-mikes.
For AC/DC receivers, a 250V rating may be good enough.
For others, check the B+ voltage to see: receivers often didn't
use as high of plate voltage as transmitters did.