Thread Nerd Necro:
I was organizing some stuff this morning and came across two old GPS receivers, a Lowrance Global Map 100 (circa 1997) and a Lowrance Hunt (circa 2004), so I powered them up to see what they did.
Interestingly, both are within [DMm] X x.005 of my phone's GPS for both lat and long. The Global Map 100 doesn't show a date, only time*, which was actually correct for my old time zone, and it let me update the time. The newer hunt, which was made after the last rollover, very strangely showed an initial time of 1457 5JUN2057 (it was 0845 local when I checked it). It also refused to let me update time and date. Everytime I input updated figures and saved, it reverted back to the future.
When I have the time, I still need to break out my Trimble survey receiver, which was built a year after the last rollover, to see what it does with DGPS.
Anyways, I thought it was interesting that despite the time being off, both the older receivers were still workably accurate. The older Global Map was in a tinfoil hat small Faraday cage I keep with the GPS, weather/SW radio, spare batteries/charger, LED lights, and a few other electronics for the Zombie/EMP/Carrington apocalypse. :)
* I think it will show the date as a string if I plug it into a computer, but I have to dig around for some com cables and a converter to see.