False alarm; nothing to see here. The guy in that shot is just an extra sporting a ponytail. EXTREME PREJUDICE was a 1987 release. Goldsmith was not yet wearing that hairstyle when I saw him in concert in June 1989.
Goldsmith was a busy man (fortunately for us). Figure he wouldn't have been likely to travel to Mexico or wherever PREJUDICE was filmed, just for an anonymous walk-on in a picture for a director with whom he had no track record.
What's really crazy is the lighting on the guy in the truck. Based on the lighting in the scene he would be in complete shadow but there is a reflector and/or light inside the truck illuminating his face.
Also, whoever the ponytail person is, they're really rocking some serious jean jacket attire.