I have a "vintage" Conoco Tank truck, which was produced by a company in Iowa. Many of these miniature reproduction trucks which use logos of well known companies are done so with the cooperation of the company itself, which may help pay production costs as a "give-away" or market them for advertising purposes. In any event, they are often authentic.
My 1:42 Conoco ( early 50's era) Tanker has a Green tractor and silver trailer. The Conoco logo with the upside down triangle has always been red and white, I'm sure.