Your radio should already have a 35Y4 rectifier tube. If it's 35Z3 replace it with 35Y4.
Check the schematic for Crosley Model 58TC, available here on Nostalgiaair. This radio is similar but has the light. Notice the minor changes required.
Norm
: I am restoring a Crosley 58TL, that apparently did not have a dial light from the factory. There is a provision for one in the set. How hard is it to add the additional circuit on the filament string to support this feature?