Model G or Model CO, I think, and it might be as young as early '50s, but I'd bet on mid-late '40s. I don't know enough to tell you what bits it lacks, unfortunately, but the chaps at Hitchcock's (
www.hitchcocksmotorcycles.com) would not only know, but could probably sell or at least direct you to the missing bits. Hitchcock's has a pretty good stock of old Enfield parts - I imagine you could find the great majority of the missing bits there.
The mention of originally having "army green" paint and belonging to the Newfoundland Rangers suggests to me that it might be a WD/CO.