Yes, that is exactly how it is designed to be attached. From experience, I can tell you that the angle bracket is not robust enough. It will flex, and it will flex the lip. There is just too much off-center leverage on the bracket.
What I did was cut my own angle brackets out of 1/4" steel angle — two sets, so there was one on top and one on the bottom, on both sides. Note that because the lip is at an angle to the bar, these brackets have to be wider than you might think, and the holes for mounting the bar have to be offset in the brackets so that they are vertically aligned when mounted. I wound up trimming the excess corners off my angle brackets, for neatness, and to clear the lower radiator hose.
By clamping the lip between the heavy brackets, it eliminated the flex.
If you are interested I have a template for cutting the brackets.
