Okay. Here's the skinny. I called Corbeau today. They had actually responded to my email a few hours after I sent it on Friday. I was out in the garage so I didn't notice until they were closed.
The guy was polite and helpful. They said that the floor pans in the pass. side weren't very consistent. so they did the best they could. I suggested to them that they caveat their sales in the future with that information to avoid surprises like this.
They gave me three options...
First, I could return for a full refund.
Second, I could modify the bracket myself
Or, I could send the bracket back, with measurements for the mounting points and they would do the modifications and send it back.
So, there it is. Not perfect, but they were willing to make it right.