Button fell off original RVD

So I don't know what was holding the button on this entire time -- near as I can tell, it's nothing more than a metal or plastic disc -- but whatever it was, it's not working anymore. After putting the button back a few times, it finally fell somewhere I can't find. I found that it still works when you put where the button used to be, but many visitors seem freaked out by the appearance and don't press it. So I replaced it with a plastic sticker, which worked until it also fell off. So my question is, can I safely glue the sticker on with a stronger adhesive? Or is this a bad idea and I should look into getting this replaced, as it's less than a year old?