Yes, deleting the Font Book app is all it does. You can easily replicate it by opening Terminal and entering:
sudo rm -r
Put a space after the -r, then drag and drop Font Book into Terminal. The path and its name will fill in for you the same as above. For this particular Unix command, it doesn't matter if the -r is upper or lower case.
As with deleting any item from the drive, you can't reverse it without returning the item to the drive. So if you think you may ever want to put Font Book back, copy the app to an external drive, first. All other components it relies on will still be on the drive. They'll just all be inert without the main app.
If you're wondering what the command means:
sudo (Super User DO). You're giving yourself temporary root privileges. Necessary in Terminal for this particular removal since your admin account doesn't have great enough permissions to delete the app.
rm (remove)
-r Since it's an application package, there are more files within what you see as only one item on the desktop. If you didn't include this switch, which tells rm to remove any nested items, the command to delete Font Book would fail since it can't remove the top level item if it doesn't have permission to also remove the nested items.
Or you can skip Terminal entirely and remove Font Book from the desktop. Highlight Font Book and press Command+I, or choose Get Info from the menus (same thing). Click on the lock at the lower right and enter your admin password so you can alter the permissions. Change all of them to Read & Write. Close Get Info. You can now delete Font Book without the OS saying you can't.