I did mine not that long ago the same way (thanks to edwardb's photos), and it is a tight fit, but I was able to get it to fit without having to trim. In my case it was just slightly oversized (probably about the width of powder coating itself), so I just used the force of the bolts to draw it up into the frame mount until it was flush and it went in just fine. Some frames and plates might be different, but I'd say in my case it was more akin to a light to moderate sanding instead of trimming.