Came across a 90's vintage IR controller for printing industry (drives Q-H lamps for drying ink in the paper path) that uses a single-digit 7-segment display that looks like a nixie tube (more like a white-hot wire segment) display. The 16-pin DIP socket is marked IEE-Atlas, and the single-digit display is marked "IEEFFD21 5DX C". Each digit display is 15 pin on a 16 DIP pattern.
I've done the requisite Google, but come up with nothing. The drivers on the PCB are MC14511BPC which is a standard CC LED 7-segment driver.
What are these? They don't look anything like LED segments (I can see each wire-like segment behind the glass front of each digit's display). Can I just replace these with a common LED display? Or are replacements available?