Re: TCL 55S405 55-Inch 4K Ultra HD Roku Smart LED TV
Correct. Right edge of the remote, about even with the navigational buttons on the face. There's a rocker switch for up/down and a separate mute button. If there's no mute button, you don't have a TV version of the remote.
Dan Nvidia Shield, Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.