Installed 003 (from 001), and Mac didn't blowed up.
Went surprisingly quickly, compared to previous updates, despite at least 3 reboots. 10-15 minutes total. It was also nice of Apple to post the standalone updater package in a punctual fashion this time, so that's what I used.
As Mr. Grouchy, aka Macintouch notes, some of the iTunes components were also modified during the process, but not reflected in the version number. That's in addition to the MobileDevice framework update needed for the 14.5 updates within iTunes itself.
Now all of my Apple stuff is fully patched; first time in a while I've thrown caution to the wind and done that without waiting for others to catch the bugs. Hopefully it won't backfire.