Actually at first they DID use the regular reflector style...except they were in 90 degree cut off angle.....but they redesigned the reflector in early 80s or very late 70s for specific controlled lighting distribution...
yeah, Dave (Silverliner14B) told me he lives in area that uses all...GE M-400A1 FCO, GE M-400A2 FCO, GE M-400R2 FCO, GE M-400A3 FCO, GE M-400R3 FCO.....he told me personally what he sees from Best to Worst light distribution.....Best M-400A2 FCO, M-400A1, FCO, GE M-400A3 FCO, GE M-400R3 FCO, and the worst is GE M-400R2 FCO...) That's what he saw as he compared them..
I might as well tell you guys that this is my M-400 a2 FCO with my M-400 r2 reflector to make it look like a new light. I was doing it as an early April fools Joke. xD
That sure got me I was almost becoming suspicous because the Powr/door was EXACTCLY the same as your FCOs. Now i know the truth. If you find a door on the ground, or someone here does and the don't need/want it, then they could send it to you and you could make a completed M-400A2 SCO.
oh what the heck
Aand.. The older one was made in 2007 and the newer one was made in 2009. 2 years apart.