Yes, they do look similar, but with the 05 being higher rated, something is different. To get actual fact, it's best to give B&W a call. It is nice to be able to talk to a real person, that is friendly, knowledgeable, and will hook you up to another person, if needed, to answer your very question.
My thinking...the base, where mounts attach, and maybe the locking to puck attachments themselves are heavier duty.
I would trust the 3300 to the full 20K rating, without concern!
Jerry