I've been looking at some Sword Art Online Skin Stickers but it says that they are meant for the PSP 3000, from the looks of the images the only difference I see between the 2 models is that the metal ring around the back is slightly thinner

So I'm wondering, with the PSP 1000, 2000 and 3000, what differences are there with size that could affect how a Skin Sticker is applied?

Here's a Link to one Skin Sticker: http://www.amiami.com/top/detail/detail?gcode=CGD2-53255