Taken from the 737NG FCOM - Opeartional Limitations. Aircraft operational in areas of magnetic variation. No option to switch to degrees true.
Maximum flight operating latitude – 82° North and 82° South, except for the region between 80° West and 130 ° West longitude, the maximum flight operating latitude is 70° North, and the region between 120° East and 160° East longitude, the maximum flight operating latitude is 60° South.
MNPS requires Dual FMC and HF comms fitted under our regulations. I can't speak for flight within Polar Airspace, however I'd imagine requirements are the same.
