Yes it is that simple if that's the way you want to do it. Another option is to do what I did and have Mesa send you a pre-wired jack plate so you can run it either stereo or mono. They sent me a pre-wired 4 hole plate with the last hole plugged up, all I had to do was solder the wires to the speaker terminals and that was it. They shipped it to me for $16 total.
At the time I was running a stereo rack, now that I'm not I was glad I went this route because I can still run the cab in mono without having to rewire the damn thing. Once it is run stereo, the cab will be 16 ohms per side.