Lamp selection for bizarre, odd ball receiver?

I recently picked up a Montgomery Ward Airline receiver. Looking for a lamp for the signal meter. I pulled the bulb out and there are no markings to ID it. I've looked for a shop manual for this, but there is so little info on these units. The bulbs for the tuning dial appear to be the same, and they are actually wired in parallel. So I'm trying to figure out the voltage and mA's of these bulbs.

Any info would be appreciated!

We're going to need a whole lot more information than that...

... like some pics... and also voltage the bulbs use, and whether it is AC or DC.

A model number or name for the unit would also help.

The unit is a Montgomery Ward Airline GEN 6901-A. The two terminal posts where all three bulbs are soldered in parallel to reads 6 volts AC when unit is on.

If it's just illumination, it's likely the same as the dial lights. Parallel wiring means you can stick the same bulb in there.
Thats's not a bad looking unit, btw.