1948 fabric sheathed outlet wires, can I ground to box?
A wire from the receptacle to the box is still no ground at all - the box isnt grounded.

You need to either replace the wire all the way back to the electrical panel to make a properly grounded outlet, or replace the outlet with a GFCI, which provides the protection a ground wire would.  You are also supposed to label the outlet with a "No Equipment Ground" sticker.