OK, but imagine seeing the exact same hat with the exact same color in a poster, the others being duplicates.
This script requires the Element Viewer which is very complicated, but can make good outcomes if carefully used.. Although, some of the guys on SFM Box seem to report there being glows around the hats, must be the burning effect!)
You may not have figured either, but VMTs with $blendtintbybasealpha (like on the many cars in L4D, or the original Common Infected), an alpha channel and starting tint with white means they are colourable. (Or are intended to have different colors)