In 1974 the shop for which I worked ordered some Columbus, SL, SP, PL, PS. Rubber stamped on the ends of the boxes along with the tube lengths, A, B or C for the various size ranges of bikes the sets were designed for. A builder could order crates of the stuff, there, tubes were bagged and tagged. Along with boxed sets such as RECORD. The frame labels were the same for all.
PL and PS were the track sets, round fork blades. The PS had 24 mm diameter blades, the PL, 22 mm. The PS chain stays were super sized and swaged down to 22 mm to accept the bottom bracket spigots.