I don't believe it
Apple Legal calling the COO of MS and asking them to stop running the ads sounds very unlikely. Even if there were specific grounds for claiming false information (and I don't see such myself), lawyers just don't do things that way. If you consider that he might just be making the whole thing up, that's even funnier (he's got to make up stuff to sound like the commercials are working).
The irony of the ads is that they show how well the Mac/PC guy campaign is working. Now instead of saying how great Vista is, MS is indirectly claiming the OS (Vista vs MacOS X) doesn't matter, that either is just fine and all you need to think about is price. Vista is no longer claimed to be better, now its just as good as a Mac.
Further crazyness is the idea that MS will be opening retail stores (what ARE they going to sell there, zunes? ) next to Apple Stores. If they do so that is really admitting that Apple is getting to them (so I doubt this is true either, they may open retail stores, but I doubt they will try and position them near Apple stores). The idea that they are doing it to build "brand awareness" seems crazy as who on the planet does not know about MS?