Each bag has four screws (two up, two down, fore and aft).
The mounts (which include a rear tip over guard level with the engine guards in front) don't come off with those four screws, but most all maintenance can be performed with the mounts on. The mounts also have heat shields under the bags to protect them from the exhaust.
Tourer bags are hinged for opening.
Twin rails around the bags are not stock but add-ons, and mount to the bag mounts, not the bags.
Here's the mounts with integral guards. The bags drop into them.

This is the add-on bag rail kit.

You only need the bag mounts to protect the bags in a tip over or a slow speed fall and slide (but not a tumble). The bag rails look great, and do help from bumps and rubs and car bumpers if you turn too sharply. They stay on with the mounts when the bags are pulled.