I didn't see many FCOs in MD until roughly 1995......I know a small group of GE M-400A1 FCOs in MD...which I remember seeing way as far back as 1986....but haven't confermed what reflector it has....I always saw it from eye level while traveling past it on a raised road and the fixture was on the lower level...
As far as I know, they aren't interchangeble.....the latch is slightly different and the front part the rim is smaller.....meaning there's no pointy front, I believe the front area space was elminated on the newer R2
What is the voltage of this ballast? The insides of this look VERY similar to the insides of my M-250 R1 FCO. It also looks like this fixture has a reactor one-coil ballast, like in mine. Mine is wired for 240 volts, and can only be used for 240 volts as there are no single-coil 250w HPS reactor ballasts for 120 volts.
Is the socket on this Adjustable? Mine doesn't seem to be.. The socket is just directly screwed onto the reflector with two screws, no brackets or anything.
Wattages under 200 probably had an adjustable socket. See how close the 250w lamp is to the edge of the reflector? There's really no room to adjust it...