I would say yes, but I'm not too sure either. Just be careful when you order, though.
I do know that when you order PPV through the phone line, it only authorizes it for that particular receiver. I don't think DirecTV changed any of that. I do know that ordering through the phone or online authorizes the PPV showing for all receivers, but there is a fee when ordering over the phone. There should be no associated fees when ordering online.
I would imagine that ordering PPV is like your regular programming. You get the channels in HD as long as they are within your subscription package range. But special event viewings like that may not be the case. I would also recommend hooking up a DVD recorder or a VCR to your TiVo unit as well, as I believe the newer software is deleting PPV showings after 24 hours of watching it (I haven't confirmed it, someone else may be able to) but it never hurts as a safeguard.
On another note... I know we have plenty of technicians on this board (myself included) but do we have any CSR's for the respective company as well? Or do they steer clear because they are the source of our call-in pains? lol.