Thanks for the replies. The altimeter in the link FLYBOYJ posted looks exactly like it, despite the slightly different model number, Also, I've found this photo :
of a P-40E cockpit, which is a little blurry but seems to have the same altimeter (just left of the compass). As far as I know...
My grandfather served in the Royal Australian Air Force through WWII, initially as a mechanic. He was stationed in New Guinea for a significant period of time. After returning he gave my father an altimeter from some kind of military aircraft, which my he then passed on to me. My father didn't...