Making sure the serial sticker stays on

I have an old light sixer from 1980 that I just put Longhorn's mod and a pause kit in. It had a pretty rough video to begin with and some of the switches were squeaky. I replaced all caps, 2 selector switches and cleaned everything up.

Everything works great so far. A problem I see is the silver sticker on the bottom is starting to come off. How would you guys permanently attach it? I was thinking of some kind of clear spray. Serial # 366217

I don't think tape will work.