What is this display on the 737 Classic?
The display you mentioned is the Universal Avionics MFD-890R. Page 15 of this document shows the screen in question. I suppose it comes with the new CDUs for a new FMS, as mentioned by Ralph J.




  Incorporating EFI-890R hardware in a single stand-alone Multi-Function Display configuration, the MFD-890R meets the needs of operators who want to incorporate additional capabilities in the aircraft like moving maps or charts, but have limited time or budget for an entire flight deck retrofit. The MFD-890R is fully compatible with the EFI-890R and can be used as part of a complete flight deck retrofit at a later time.