1. I would notify Steve as he needs to be aware of this from both a customer satisfaction and a quality control point of view. Sounds like the factory erred.
2. You could grind down the top of the bracket, or hacksaw it some to fit.
3. You could drill out/elongate the hole sufficiently so that the bracket fit.
4. If it were me, I would do a combination of 2 and 3, a little here, a little there. But still inform Steve of the issue.