I would tend to agree with ourworkbench about being a factory refurbished machine. I would say a bit later than early 40's (late 40's?) due to lamp style (style 4 spotlight), but that could of been changed out through time (but the condition of the wiring makes it looks not so imo).
Would also agree with sewbizgirl that it started off life as a treadle machine.
Interesting machine indeed.
As for the belt, V Belt or cogged....both are fine. One spool pin if I remember correctly
