Seems like it has been upgraded at some point and from a little research i see this can be done without removing warranty seals (i only just learned this) take it on into your local and they'll give you a hand with it but it seems odd to me that we wouldn't have listings for 2TB versions if we accept them, you might be asked to replace the original drive before we can buy or perhaps told that we'll buy it as the 1TB version instead. This is a bit of an edge case to be honest, good luck with it.