My guess is yes, they must be attached some way. They are not in air-tites and they aren't recessed into holes, so they must be stuck with tape or glue.

It could be difficult to impossible to remove the adhesive without damaging the chips. Of course, if you get them cheap enough, it may not matter.

Another thing to consider when buying chips in a frame is damage from fading. You may peel the chips off and find that the other side is noticeably brighter than the side being displayed.

Greg