Unless you're on the mini-pill, an hour late won't matter, and won't cause you to spot either.
Most birth control has the effect on me of making my period go away all together, so I don't have this problem.
However, I've heard it can happen, and I know that off of birth control, we can get random spotting for many reasons. Stress, food, exercize, diet, etc..... it's probably just an anomaly.