The bracket that holds the can came with it. I mounted the bracket to the brake booster (take off the nut holding the brake booster, slide bracket over bolt, replace nut).
Yes, the silver doohickey is a one-way check valve. I bought the kit that included the valve and the clean side separator. Like I and others have said, you really don't need to install the CSS, and you really don't need the check-valve for these trucks, but I have it and decided to install it anyway now while I was doing everything else. I may install the CSS later since I own it, or I will try to sell it. IIRC, the entire setup from Elite Engineering with shipping and the upgraded braided hose cost me right at $400.