Yes, I saw that post, and those numbers work for O and S gauge. But since Lionel isn't using the 48- prefix for O and S, and the 87-prefix for HO, the HO Marketing Categories and O Marketing categories conflict with each other, For instance xx22xxx is "O Gauge High-End Sets" in the 48-prefix list, but xx22xxx is "Steam - Mid Range" in the 87-prefix list. It appears when Lionel decided not to use the 48- and 87- prefixes, they had to revamp the 7-digit system (at least for HO) and assign different Marketing Category digits for those.
Of course, I'm also hoping someone knows of additional pre-2018 6- 7- and 8- numbers that have a specific meaning (rather than being random). I've listed a few on the spreadsheet that seem to qualfy -- but I don't know if they'r accurate or not.