My apologies...poorly chosen, jumped the gun wording...let me clarify. Per the publication, Collector's Originality Guide - Mustang 1964-1/2-1966 by Colin Date; MBI Publishing Company, Copyright 2002, 2009 he states on page 46 that,
"All major items of the Mustang's interior are color-keyed to the wide choice of upholstery colors. The sun visors and the headlining in the hardtop are of white textured vinyl which emphasizes the spaciousness of the interior"
Bottom line is that, apparently there are any number of non-white examples that makes the authors statement somewhat cavalier and subject to misinterpretation. In my case because I did find original white headliner under the replacement and that I discovered from the previous owner just this morning that they had replaced the old "white" visors, is good enough for me to go ahead and use white.
Thanks all.