A comment there confirms my thought when I looked at the numbers:<p><i>the IBM PC division kept up that numbering scheme (4-character “type” code, followed by 3-character “model” code) all the way up to when they were sold off to Lenovo in the mid-‘aughts. (It’s also possible that Lenovo has continued it to this day; I just haven’t kept up with Lenovo in recent years, so I’m not sure.)</i><p>...and yes, Lenovo continued with it until around 2012:<p><a href="https://psref.lenovo.com/syspool/Sys/PDF/withdrawnbook/ltwbook_WE_2012.pdf" rel="nofollow">https://psref.lenovo.com/syspool/Sys/PDF/withdrawnbook/ltwbo...</a><p>They switched to longer part number codes after that:<p><a href="https://psref.lenovo.com/Product/ThinkPad/ThinkPad_P16_Gen_2" rel="nofollow">https://psref.lenovo.com/Product/ThinkPad/ThinkPad_P16_Gen_2</a>