Hey Nex...
Cost has little to do with features or image quality; for a couple hundred more you could get an intro dSLR with a kit lens that blows the sensors off every single PowerShot ever made.
Regarding firmwares, though... the odds of you getting a firmware revision different from every single other unit in a specific warehouse distribution hub is astronomically small. Certainly not from a retailer the size of Walmart. It
can happen as fe50 points out. But the changeover takes days, not months. This is Continuous Flow Production... the stock must flow.
(sorry, Mr. Herbert)Downgrades are a flat "no". Consider, sometimes firmware revisions are tied to a hardware modification to correct something, or tied to a batch of consecutive serial numbers (assembly probably had a part out of stock and used a substitute in the pick-n-place.). Which is why no one ever suggests "tricking" or forcing a firmware update from a version not specifically applicable. You could brick your camera.
Best advice, just buy the camera you want. :^) If it's possible to port CHDK to it, it will happen eventually. You might even be part of it! If it's a supported camera but a different firmware, sometimes the CHDK for the previous firmware works fine. There's many models that are working like this already. If however you truly
need CHDK for whatever reason, then buy one of the cameras currently in production that is supported, buy old stock, or buy used / refurbished cameras.