Found this paragraph on the histry of Chrysler on the net this should explain all of your questions.
The Pentastar appeared consistently but inconspicuously on the lower passenger-side fender of all Chrysler products, including foreign brands, until the early 1980s. At that point it was adapted to appear in such forms as trunk emblems and hood ornaments, replacing other designs that had been used by Plymouth, Dodge and Chrysler and had in some cases identfied individual models, such as the Chrysler New Yorker. It was placed on the passenger-side fender so it could be viewed by passers-by, a subtle method of getting the symbol ingrained in the public's mind. A nameplate has to be read, but a symbol is recognizable even to the illiterate. Thus North American and French cars had the Pentastar on the right fender and British on the left.
Also I found a pretty decent picture of a 70 Challenger R/T with a closup of the passenger fender.
Hope this helps!
