I'm in love with this old girl, I love lowtop M-Ms, especially ones with the typical CA amber beacon ray. Plus this one has factory tunnels to boot, somewhat unusual on a M-M of this vintage as they more often had Ful-Vus. A somewhat sure sign that she was built as a straight ambulance, not a combo turned into an ambulance. But I guess clear windows might prove me wrong and reveal rollers on the floor!
It also appears she may have once sported a siren on her passenger side front hood area, possibly a Q?
This girl might have once been set up similarly to Robert Shepard's 1966 C/B that he once had when he owned his ambulance service, that I am also in love with. Although Robert's didn't have tunnels though, and his had dual red beacons up front with a CA steady burn red lensed light between them (and a single amber beacon ray aft). But his had a Q on the right front hood area, too, like this one possibly had at one time.