I agree, the 82-080 looks like what you have here. We don't have a video on it, unfortunately, but it's not that difficult to install. You just put it on the door and screw it in. Note that our screws come in from the sides.
As for the mortise lock not working, check to make sure that the anti-slam button in the middle of the mortise lock is depressed. The reason this function exists is to prevent you from closing the door while the hooks were extended, which had a tendency to break the door in all kinds of messy ways. It happened more often than you'd think. The anti-slam button is a quality of life upgrade present on most modern mortise locks.