You want Plasti Dip, not a sealer. Plasti Dip is made to cover items, but is easily removable if you do not like it.
I do not know of anyone who has sprayed a faceplate, but it certainly would work. When applied well the product looks good. I have seen entire cars and motorcycles which have been sprayed.
Nice! I’ve found several directions on its use in metallic surfaces (e.g. cars) but not plastic despite the product’s name. Do you know about special instructions / tricks on how to use it this way?
One more thing: any hint on how to protect the labels during the painting?