A couple years ago I stumbled across
this replacement cigar lighter at Oreillys. It fit like it was made for '51 and the black plastic cover does a good job of hiding the upgrade to the 6 volt truck. I carry a two port plugin charger and it works like a champ (phones only require about 5.5 volts to charge). One step I did take was to wire it to a constant hot so I didn't have to have the key on to charge. No pics but can throw one up if anyone is interested.