Yes it is true that the pentastar was on the lower right fender but it had NOTHING to do with a warranty.
It came on all Chrysler--Plymouth--Dodge-from the mid sixties to the mid seventy.. I'm not really sure when it started or ended but my 67 GTX has one and so does my 70 Challenger.
AL
The Pentastar was only placed on the right front fender and its usage is traced back to the 1920s when wealthy car buyers would order a car with a custom built body. In these instances, a car buyer would order the chassis which included the powertrain, all four fenders, hood cowl and lights. THe body builder would then construct the body to place on the chassis and this builder would include their body builder's plate, which traditionally was located at the base of the right side of the cowl. When Chrysler adopted the Pentastar as their corporate symbol, it was meant to incorporate the five divisions of the corporation. Chrysler, Plymouth, Dodge, DeSoto and Dodge truck. Given that the Pentastar was created about the time DeSoto went away, Imperial was substituted as the fifth element of the star. Since cars built when the Pentastar came into existence didn't have exposed cowls, the decision was made to place the star at the base of the right front fender.
Any car which has a Pentastar on the left fender got it by the owner's choice or it was a mis-build at the factory. There was only ever suppposed to be one on the car.