You've got that right. I suspect they will for a couple of reasons. The first is that McCain holds a grudge, and Romney took a few swipes at him in the primaries. The second is that his campaign has been doing things much smarter than I am used to from the GOP during elections, and this *is* such a smart pick that I find it hard to believe they won't do it.
That is you. McCain whompped Romney, who spent one of the largest amount per votes, ever. Like him or not, McCain is a winner, and that means he knows what he is doing politically.