It is always ideal to have parameters within the recomended condition so if it is possilbe to raise the pH before the rock arives than do so. That being said, if the live rock and live sand is not from an established tank , it will reak havoc on the tanks acceptable nutrient levels for the first few weeks (possibly longer) and given your filtration power will more or less throw your ionic balance out of whack as you compensate with water changes, mechanical filters (protein skimmers, foam filters) and chemical filters such as activated carbon. Activated carbon and protein skimmers can remove the supplements you add but will remove the ammonia (which leads to nitrites, followed by nitrates) that you with out doubt will experience during the acclimation of live rock and live sand addition while organisms die off (less so on cured rock and sand than non-cured). That too being said, leave the carbon in (and change as recomended), as the benefits of keeping the carbon will outweigh the benefits of taking it out during at least the first month of live rock and live sand addition as the system reaches an equilibrium. After that, even the experts argue whether activated carbon is beneficial.