When purchasing a pump, tank, or valve, also purchase an inexpensive engraver, and engrave the model and serial number in an alternate location that is more visible than the nameplate. Not only will it be easier to see, but when the nameplates become unreadable you will have an alternate area for that information, or you can engrave an aluminum tag and chain it to the said item.

The point being, model and serial numbers often fade or become unreadable with age, having an additional spot on the piece of equipment will make life easier when it comes to identifying that item in the future.