Hi Chappers, I presume in your question you mean radio gear fitted circa WW2, rather than post war ? in which case No, there was not a radio installation mounted in the cab. Although thats not to say there werent occaisional field mods made by some enterprising outfits.
Both SCR 339 and SCR 499 sets were fitted in some Workshop Bodies as "official" gear, with the tel-tale MP 50 antenna mount at high roof level.
Immediately post war there was a trend to upgrade trucks with radio units and this was particularly practiced by the French with trucks serving in North Africa. It was not uncommon for them to install High Power, long range sets in Cargo trucks, but because of the physical size of this stuff it was not usually cab mounted.
Several cargo trucks in the UK reenactor groups have tended to sport MP 50 mounts with short arial in recent years, ..........perhaps one of those owners could bring something to the party.