No need to guess. It was previously posted above, prior to new HO line. Again, here is how the numbering system works:
Lionel new seven-digit numbering system
Effective in 2019
-First two digits are the year of introduction.
-Next two digits are the primary marketing category. (For example, 26 is for full O scale rolling stock, 28 is for O traditional rolling stock, 31 is for full O scale steam locomotives, 32 is for O non-scale steam locomotives, 33 is for scale diesels, and 34 is for non-scale diesels. See image below for full list of other categories.)
-Last three numbers are the product stock number, which differentiates items that share the same first four numbers. (Road numbers are also included as separate stock items.)
Take, for instance, Lionel no. 2031261. That’s the excursion version of the Big Boy. It’s a 2020 introduction (thus “20” is the first two digits). It’s a properly proportioned O scale model (thus the “31” in the next two digits) and is stock no. 261.
Lionel no. 1932040 is Pere Marquette Berkshire #1225. It’s the LionChief Plus 2.0 version of the Polar Express Berkshire that has been included in trainsets for more than 15 years. It’s a 2019 introduction (19), is traditional sized (32) and carries a no. 040 stock number.
Lionel no. 1933151 or 1933152 (Wisconsin & Southern SD40-2 #4001 or #4003) is a 2019 introduction (19), full O scale diesel (33), with two different road numbers (stock no. 151 or 152).
Here’s a chart we have been sharing on the forum indicating the product coding for the two digits that follow the year.
