There is no "style guide" of any kind for this report, or any reports in this company. Formal reports aren't too frequent. This is a mostly internal report, though it may end up with a consultation rep. The audience is generally my own manager and coworkers, though it is possible it makes it up two or three levels.
This is my situation, which may help refine the answer. But is there any reason I should not include the company logo on the cover page?