National brand water heater?

Help, I can’t find anything on National (Glassteel fast Recovery) electric water heater. Serial # is 76-680463. I can’t believe the thing is 30 years old. National brand is not listed on any of the decoders I’ve got. Anyone?

I don’t run into Nationals up here.
Did it have an ANSI date on it?..that’s usually within 3-5 years of manufature.

No, no ansi date unfortunately. Had a blanket covering most of it.