The M-150 was the boxy version of the Current M-250A2. The boxiest one was the M-150, the boxy ones was the 1st generation M-250A2, and the more rounded one made todat is the 2nd generation M-250A2. I personally have never seen the M-150 name used by GE, I've only seen the M-250A2, but I've heard the name used. Can you post the article? The fixture may be rare, but it looks almost identical to the 1st gen M-250A2, so it's hard to say.