I didn't play when the game had subscription if that's when you could do that, so then they changed it or introduced that property on some items (and like all the wings have it) after it went free to play cause they need to make money out of the shop to keep going. But they still also put it on some in game equipment and if you like the skins you have to drop them multiple times. For me I like Tiamat and RST skins and they both can only be remodeled once.
The thing is you probably can't pull stuff from older versions cause either stuff gets deleted or altered heavily, also some variables may change and some call outs might return different things and that might break the game, else we could have aion 4.8 with sarpan, tiamaranta, katalam and danaria still there. Or having 4.6 with the 4.8 gameplay changes that are really nice.
Well the warning about not being able to reuse the skin is like in the item itself, the remodeler is used for every type of item so there's only the warning that your item on the bottom would be destroyed.