Permag charging systems suck, they can only charge at one rate as adjusted by rpm, the excess charge not used simply bled to ground, they overheat parts more. Motorcycles have hell with them since rpm range so wide. Variable field stuff like 6G on Focus simply moves the field current up and down to vary the charge rate, more dependable even though a little more complicated.
Some VR color code stuff here......we use second type listed I think, or white body with black small cover. Ford OEM numbers at top of the page.
This page seems to infer that there can be a couple of other colors that will work, they are later versions of same part, look at the BOTTOM of the page, the last 3 listings.............note the Dubois #102062 covers them all.