1971 Twister

body side molding was somewhat of a popular aftermarket item back in the day.

you should be able to tell if it's factory-

aftermarket is usually glued on
aftermarket is usually cut to length

factory usually has some holes in the body and some studs welded on
factory usually has a metal backing that is the correct length for the panel in question with rolled ends

...and the tag code

plus it's super easy to slap twister stripes on any Duster.
I've seen many.