Not that I have the family pack, but it would make sense to ship at least two DVDs in the box.
Why?
For those folks who have a mixture of DVD and CD machines - the media exchange program requires relinquishing the original Tiger DVD, which seems a little unfair for Family Pack buyers.
(I know, the alternative in this case is to use Firewire Target mode to install onto the CD-only machines, but that's more of a community-suggested workaround than a method that Apple openly advocates)
My expectation however is that the box has just one DVD. By now there should be at least a few MR members who can tell us for sure..