Originally Posted by DeNomad
Since the bottles will be sealed at sea level (or whatever altitude you live at) I would not worry about it. The only pressure that is going to be changing is the atmospheric pressure and since the bottle is a rigid container the internal pressure will be unaffected by the change in atmospheric pressure.
Upon opening the CO2 might fizz out a little more quickly but I wouldn't worry about it.
The difference in pressure is about 3 psi at that altitude. I don't know how much this affects the rate at which you'll lose CO2 when you pop the bottle, but I can't imagine that AB or any big beer companies carbonate differently for different altitudes.