LCDs Rule
I am no longer a Polaroid as I 'retired' at Age 60, but I was there a long time so I do know the answer. All the Polar 400s were ordered by GE at the same time and were identical to each other. When new they all had CRTs but it was decided a few years ago that they would be replaced with LCDs when a replacement became necessary. This was due to increased reliability and a longer shelf life. Therefore, the aircraft may have different types of screens, or even an intermix. As with TVs so it is in aviation...LCDs rule.