You better go ahead and activate them now to get your new free G3 cards because once the card swap is over they will want $50 for each card in order to get them activated. Once you receive the new cards have them send down a hit with the new cards in them then tell them to deactivate them.
You better plug it in for several days followed by a check switch test before you try to activate them, 2 years behind on software causes lots of activation problems.