For example, if it doesn't have the stats, it could have the word "Skin" attached to the end or something. Because I think right now, whether it has stats or not, they both have the same name and it's really confusing :T. The description could also be changed. If it's the stat version, it could say something like "When worn with the matching wings, it gives bonus stats." If it's the skin version, it could say "Skin item. Does not give bonus stats when worn with the matching wings."
Example (names)
Stats -> No stats (Skin)
Angie Head Band -> Angie Head Band Skin
Colorful Balloon Hat -> Colorful Balloon Hat Skin
etc, etc...
Example (Description)
Stats (Now) -> Stats (After)
Skin item. -> When worn with the matching wings, it gives bonus stats.
Skin (Now) -> Skin (After)
Skin item. -> Skin item. Does not give bonus stats when worn with the matching wings.
etc, etc...