Product Numbering & Bar Code Verification of Phantom Plarail Sets

I found another N-22, from the ターミナルステーションセット which was also manufactured in 1974 along with the ハイウェイぜんじどうふみきりセット. Notice these 2 sets have the Plastic Highway system, which is the first generation of Motor Tomica.



I collected information from other sets released the same year, and as per my expectations, they are all G-22. I'm starting to theorise that the N alphabet is to mark sets that contains Plastic Highway, and G marks sets that are in the normal line. Plastic highway was also manufactured by TOMY, but wasn't really a Plarail as those Plastic Highway had their own sets without the Plarail mark. G-22 is a period from 11/1973-10/1974, but I know that the sets are confirmed 1974 from a catalogue. The single item wise, might be 1973.



Moreover, I also realised that one ST mark is a white sticker (curiously a sticker and not printed) on one box, and the numbers are close to each other. So they are registered safe-to-play in the same period.