Is it possible to remove items from "System Settings"

Given that changing the permissions accomplishes your goal, check out this magic:

dpkg-statoverride --update --add root root 640 /usr/share/applications/gnome-printers-panel.desktop
dpkg-statoverride --update --add root root 640 /usr/share/applications/gnome-info-panel.desktop
dpkg-statoverride --update --add root root 640 /usr/share/applications/gnome-keyboard-panel.desktop

You can remove the overrides with:

dpkg-statoverride --remove /path/to/file

(but note this won't reset the original permissions)

OK, I think I found a workaround -- gnome-control-center doesn't respect Hidden=true in the gnome-whatever-panel.desktop file, but it's not smart enough to display a panel if you completely remove the associated .desktop file.

So for the panels I've listed you can remove/disable them by deleting the following files:

/usr/share/applications/gnome-printers-panel.desktop
/usr/share/applications/gnome-info-panel.desktop
/usr/share/applications/gnome-keyboard-panel.desktop

As MikeyB noted in his comment making these files unreadable by "other" is also an option - I tested this (chmod 640) on a spare box and it appears to work, disabling the panels for "normal" users while still leaving them available to root and members of the root group.

There are two notable disadvantages to this approach:

1. This completely disables those panels for ALL users.
   You can't even invoke them manually by running gnome-control-center info or similar as Radu Rădeanu mentioned - They just won't launch.

2. Updates to gnome-control-center & related packages may bring the panels back.
   This basically means checking after each software update to be sure they're still gone (or have appropriately restrictive permissions), and deleting/chmoding the .desktop files again if necessary.

For my purposes neither of those are a huge issue since I configure these machines from the command line anyway & the system settings panels are just for users to make minor "personality tweaks" so unless this workaround

No, unfortunately you can't remove any of Printers, Details, or Keyboard from System Settings. These are called "PANELS" and are hard coded in the gnome-control-center package. If you remove this package, you will not have System Settings anymore.

Let say that you remove those icons and names from the main panel of System Settings. Anyway, a user can open any one of them from terminal using one of the following commands:

gnome-control-center info
gnome-control-center keyboard
gnome-control-center printers

See man gnome-control-center for more info.