Hi Paul,
Thank you for your reply, but that advertisement is really misleading. The photos and the descriptions bear little resemblance to the real 2042 and 2052 models. The only Cordaway models in this line up were the top of the line 2082 and 2092. Not quite sure why the retailer did not know his products.
The only difference I can think of is that the 2052 may have a two-speed motor. The 2042 already had some deluxe features like a 6-position Dial-a-Nap, Vibra-Groomer brush roll, wide bumper and switch on the handle. But it only offered a single speed switch.