It depends what their warranty policy is. - I have a Samsung 930BF that was bought under their "zero dead pixel" policy, and despite the fact I bought it in Australia Samsung in the UK have honoured repairs to it.
Often the policy is something like zero dead pixels within a the middle 50% of the screen (so anywhere that's not ~25% from the edge). However if it's brand spanking new, it's worth talking to the vendor about it.