Theoretically, this is still possible
(in /isolinux/sbootmgr you'll even find an MS/DOS executable to write a disk image file to a 360K floppy disk).
Slackware's installer, which includes pkgtool, still allows you to use either I.2 MB or 1.44 MB floppies as source media.
OK you won't install everything that way - and certainly not the kernel. But *some* packages still can fit on that.
I would be pleased to know if someone still can report any real-life use case for that feature.
Otherwise I would politely request Pat to remove that from his scripts (or at least comment it out, as he sometimes does for obsolete stuff).
Keeping that even if nobody uses it anymore does not hurt. But I hope that in a not so distant future it will be possible to ship internationalized & localized Slackware's installer including package tools, so removing it would mean a little less work for translators.