I can't say for sure without seeing your unit but the Argus units I have seen in the past took the bulbs with pins on the side of their base. That would be the #5 or Press 25 or bantam 8. With an adaptor they could take the M2, M3, M5, M25 bulbs.
Look on your unit most flashguns gave a distance to subject to use with a listed bulb. The bulb listed is the one you need.