Ahh. I wonder if Cooper Lighting has any old literature from the Westinghouse, McGraw-Edison, or Crouse-Hinds eras. I know GE has all of their previous spec sheets saved at their main facility. I emailed them about receivng a PDF copy of some ads and a worker gladly emailed me the 1977 catalog including the M-250R, M-250A, M-400, M-400A, M-250R cut-off, M-400A cut-off, and M-1000 respectively. Back then they actually listed the fixture price on the catalog sheet! I'm thinking of emailing them again for a 1960s M-250R ad or an ad for the so-called "M-150A" that was the previous name for the M-250A2.