Wldthing, there are two ways to add color to a 3-D model... add a texture map to the polygons, or add a single color value to the polygon itself. My guess is that the P-51 spinner was done the latter way. Many other "early AH" models were done this way, like the B-17 for example. There is no texture to correlate these areas. You'll just have to work with it.
As a side note... some people have called these "skin bugs" and similar terms. They're not bugs; it's actually more efficient (memory-wise) to color a polygon by assigning a color to it than it is to map a texture on to it. Some of these aircraft go back to the Beta days of AH... just a few years back, when computers were 1/10th the speed they are now. I'm sure they had to count every polygon and pixel to keep playability within "budget". I'm certain that as time goes by, these planes will be reworked.
