No I took the mount out, put the slice in, added a zip tie, and put the mount back in just like the instructions say. My point was it's a tight fit even before you reinstall the mount in the car, that's all.
I don't have any opinion on the necessity of the upgraded bolt. Obviously it's good insurance or whoosh wouldn't sell it. My car has low miles, it seemed like a lot more work and I wanted a simple mod I could get done in the morning before work. If it breaks I'll deal with it then.