I have a Guide 6004 on my truck, mounted with a hose clamp, not a cast bracket. I will count the wires for you, but it's not a 7 wire unit, I know that much, I think it's a five wire, left, right, hot, flasher, indicator lamp. Perhaps that's what is called a four wire?
It is self cancelling, and works awesome, I feel like I'm driving a Rolls when it clicks off as I go around the corner! Pretty fancy for the old bus.