Hard to tell what type of display is used from the photos, but I would have thought backlit lcd. But lcd's usually share a single backlight, so either the lcd segment has issues or it is some kind of led display. You'll have to open it up and take a peek.
I'm pretty sure that is in fact a WWVB radio signal clock - they were quite common at the time. I've actually just got a WWVB kick myself and while researching I learned that the old AM protocol was updated to include phase modulation in 2012 - the PM format apparently provides better reception and additional data but requires the receiver to be PM capable. The new format is backwards compatible with the legacy AM transmission format. I feel old think that this 'update' occurred back in 2012 and is new to me lol. On a side note, I recently purchased an Everset ES100 WWVB receiver kit from Canaduino (
EverSet ES100 WWVB BPSK Atomic Clock Starter Kit - CANADUINO®)... haven't got around to wplaying with it yet but seems like fun. Though in this digital day and age I suspect that radio transmission is likely to be obsoleted entirely. People will realize their error when Armageddon comes and analog receivers are the only things left working lol.
Interested to find out what's up with that display...