That's correct, it'll show at $0 for now -- Mike doesn't accept $ for things not yet in-hand, so the pre-order is used to show interest in the particular colors/connections/etc., build up a preliminary count of what'll need to be assembled. You don't actually get charged, but you've got a place in line as it were.
(Not sure what would happen if you order
batteries and charger, as those are stock. I'd skip them for now, wait until it's time for the final order, the one where the Infinity Pro has its $ listed, just do pre-order of the base IP in whatever color and connection combo is wanted.)