Hi Wendell,
My only thoughts are that by 1937, (if you're wanting it to be absolutely date correct) Magnolia had been a branch of Socony-Vacuum for several years and I would surmise any tanker made/used at that point would be your standard red S-V tanker with Mobilgas/Mobiloil markings, possibly with "Magnolia Division" noted somewhere on the unit, like I've seen on General Petroleum trucks of the same period. I do not know this for a fact, just speculating as S-V had pretty strict standards for everything else by that point to unify the Socony-Vacuum "empire" and consolidate all of the lesser branches into the company standard.
Darin
