This would actually be a Line Materials version of the Unistyle 400. When the single door version of the Unistyle 400 first came out, two things made it a LM. The deep refractor and the rearward position of the P-cell. in the mid 60s, the P-cell was moved up but the deep refractor was retained until McGraw-Edision took over. Had this luminaire had the shallow refractor, it would have likely been a McGraw.
@ traffic light1: Thanks!