Ah, both of those buildbots are running Build Tools. Apparently there's a different layout for those.

Note that the devguide provides instructions that can't be followed with the Build Tools - you need VS Community (at least): https://devguide.python.org/setup/#windows

Hopefully by tonight I'll have proper work access so I can figure out why Build Tools don't install everything. It may just be that a configuration option was missed, and so the buildbot owners will have to modify their install.