jcode71, all 71 Mustangs with the lower accent paint received black paint (Along with black stripes if equipped) EXCEPT "A" #1724 black, "C" #3542 Dark Green Metallic, "J" #3657 Grabber Blue, and "6" # 3077 Blue Metallic. These four colors received Argent paint (and stripes if equipped).
I've seen Grabber and Blue Metallic cars with the black paint and they do look good. I feel the black does a better job of hiding road tar and other debris thrown up by the tires. Another combination I've seen and looks good but also not offered by Ford was Red with silver accent paint and stripes. In 72 and 73, 4Q, 3K, and 4C codes were added to the argent only list. I say unless your doing concours, paint or stripe it the way you like.