Hello,
I'm not a Polar pilot but a -400 driver and I can tell you that things get swapped around in the fleet during maintenance actions. So you might find a fairly new -400 with LCD displays and stby instruments but with an analogue MCP as well as any mix of CRT and LCD combinations and older aircraft with a digital MCP and so on.
They only have their original configuration until something breaks and then it might be exchanged with whatever is on stock.
Hope I could help.