If you don't want it to fall off and be lost, I'd suggest careful cleaning and use of an appropriate metal ADHESIVE rather than JB weld. I consider JB weld to be a 'metal filler' as opposed to an adhesive? Your experience may differ.
An alternative might be to have a new tag made which matches your original tag, attach the new tag per factory specs, and KEEP the original tag in your glove compartment or console?