after 11 pm "for a beer"? If that isn't code for "wanna get nekkid?", then I don't know what is. The only possible exception is if both you and your friend work late shifts. If you and your friend's normal hours are, say, 3 to 11 (so common in Vegas), then coming by at midnight for a beer is like a 9-to-5er coming over to a friend's house at 6 pm.
Assuming you work days, I hope your friend's cute