Re: Of course they're testing it again
They're two entirely different vehicles, and SpaceX has undoubtedly benefited from the lessons learned by their predecessors.
ie don't let other agencies strong arm your design team into adding their bits, like the air force demanding cross landing capabilities with the shuttle (so it could land after less than one orbit without anyone knowing where it had been) which completely ruined the proposed lift capcity.
SpaceX also benefits from not having to worry about people riding on their rockets... They want to launch people one day
But this advantage isn't that big, as they want their man rating eventually and won't plan to redesign the whole thing in order to make sure it gets it; man rating was built in from the beginning (IIRC).
Enough complaints from me; a beer to Musk for all his efforts and all those who do exciting things in space.