Judging from the lack of posts in the HBS blog today I suspect they have started reading. This is what the blog says about questions:
"Submit your questions via email to
admissions@hbs.edu and put "Questions for the director" in the subject line. At this point, I think questions should be about the application and application process"
hi0parag, I would say just e-mail them asking politely if an app submitted at 5:02 would be considered Round 1 or 2. I wouldn't ask for them to do anything about it. Just an innocent little information-seeking e-mail. They are usually pretty fast to respond.