What you are seeing is a result of the missing specularity files from older skins. AH3 renders those skins with missing files as a glass surface. Only skins created after HTC began using the specularity and bump maps in 2012 will have the correct sheen. There are many, many skins with this problem. Thankfully, we skinners now have the ability to adopt the skins from players who have left the game which allows us to make a replacement from scratch. But it will take years to adopt and redo all the skins - there's over 400 for adoption.
BTW, only 2 Me 262's will have the correct sheen, both done by me.
