I'll have to go back out and try it again to see which way is which. The bottom line, though, is that it works opposite of how it's labeled on the Sealco placard. The handle is a yellow square. The truck has a tractor protection valve (round black handle) and it works as labeled/correctly. There is no third "emergency Brake" valve, though.
Billy -- I would go back to that dopey yahoo I bought it from, but I'm afraid he'll ask me for more money as I pretty much stole the truck from him as it was

You'd probably like him if you met him. He actually reminds me a lot of you...