Yes, personal preference but I am so with you Jeff. Not only is that part of the flat terrific when cooked with the point but if I am going to the trouble to trim and cut and carry on I ain't doin Q. (Burnt ends--to me--are insipid and way overrated.)
However, we are not answering your question Jim--yes, I have cooked brisket that way but no, not on the WSM. You certainly could very easily. You may or may not choose to foil the flat depending on how confident you are in its marbling.