That certainly seems plausible for the bundle. However I am highly doubtful that the price drop applies equally. You may see a fifty dollar price drop on all the console models, but the Kinect will probably retain the same price point when sold seperately. That kind of makes the bundle appear more attractive. Which is after all the point of bundles to sell more by giving better value.
I just purchased a 360/Kinect bundle. Right now I am feeling some buyers remorse, because the bundle isn't actually some kind of savings over buying the things seperately. I confess that I bought it, because it was all shiny, but I most definitely do not feel like I was getting a good deal. Microsoft needs to do a better job of making people feel good about buying some of these bundles.