I would have thought they'd use actual Apollo footage, tarted up for IMAX and processed for 3D .. but maybe that can't be done even with computer-processed perspective shifts (one for the left eye, one for the right). Maybe that's why they used mockups and actors instead, with CGI - where the perspectives could be filmed from the start. If so, the intent must be for the 3D effect alone .. otherwise why not stay with the real historical footage?

(not that Ican see 3D anyway, so I'll probably miss it ..my great ambition is to collect as much DVD footage from Apollos 15-17 as possible when I can afford it)