I would call the hotel and find out the policy.
Last time I did this I got into Kuala Lumpur at 4 am, but didn't actually get to the hotel until around 7:30 but I had booked the night before and made a note of it on my reservation. I forgot that you still have to deal with baggage, immigration, customs, and teh airport transfer, which is 1 hr. Next time I go, I plan to book the day of and just have breakfast at the hotel while I wait for my room....