Edit: wrote from phone and sounded a bit offensive when I read on computer. Never meant it to be like that.
No, I don't think that it's glued. I have not heard or seen anything like that. I'm not a moc expert but think I opened around a 100 figures when I was a kid and at least none of those where glued. I don't really see why they would glue figures to the cardbacks either. Vinyl though can get stuck to surfaces if warm etc. That seems more logical to me. Might fall down if you shake it a bit, but if unlucky it could rip a piece of the paper which would suck.