This is not a BOSS machine. This is as you said a NC2A. An NC machine did not have a memory for the program to be stored. It ran a tape and had a one line buffer. Yes, it has stepping motors and a air over oil quill mechanism called a "spindle wizard." The Z axis is the knee. The connectors on the side of the control cabinet is for the C5 and C6 option that conveted this to a CNC.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)