I was looking at the mount the other day and couldn't quite figure out the safest way of doing it. Now I see that I can shave those areas and turn it on its side to wiggle it in.
That sounds dirty in my mind...to much time off and too much porn
You may need to notch in each side also. Honestly I'd start out trying to put it in and then grind off what ever starts hitting as you try to move it in (within reason of course as you still want a usable mount).
I might have cut a little extra but not much. Just do what has been said & cut a little then test fit until it fits. The reason I cut so much is b/c I took it somewhere to a bandsaw & didn't want to have to make alot of trips. i cut a big chunk then cleaned it up later with a grinder.