From the FAQs:
If I check-in before November 1, 2014 or check-out after January 31, 2015, do I still earn credit for that stay?
All nights of an eligible stay completed during the Promotion Period, regardless of a check-in date before the Promotion Period begins or a check-out date after the Promotion Period ends, will be counted for registered HHonors members. The first stay will count towards the promotion bonus, but is not eligible for the Double Up Bonus Points. The second stay will count toward the promotion bonus, and is eligible for the Double Up Bonus Points.