NEC wise anything you want is acceptable, it only requires identification of multiple voltage systems if present, and does not specify use of color to make that identification. Color just happens to be one of most popular methods. Code also requires you to provide legend that describes the identification method at switchboards, panelboards and maybe a few other places.
Every Delta High-Leg system present must have an orange B phase [110.15] even a single voltage site . In the unlikely event you have two different delta hi-leg's in a large facility both B legs would be orange.
I always took that to mean orange wire or orange marking tape for the stinger but it must be something orange.
It doesn't have to a color at all, it could be tags or labels and in existing facilities it should remain what color it already is.
I think high leg systems are just rare enough it doesn't get too much attention, but I have also thought this wording has needed changed to be a little more clear for a long time. But as I read it the color orange seems to be more of a suggestion than a requirement. Enforcement may be little/none to extreme.
