These are the same 2010 daylights that have been selling for over two years already. They're not specially built for this 40% off sale, the dealers are simply helping the factory blow out their stock before the updated models are going to be shipped. Having said that, you have to be extra careful and diligent with your QC, because it's possible that refurbished watches from QC rejections will make their way out in this manner.
If you missed the bus when these were discussed here's a very brief summary.
The most accurate of the bunch are the 236/250 and the 251. 188 & 196 don't have a period correct crown tube.
All 2010 model year A7753 daylight models have a 7750 datewindow position, the date font is not bold enough (more noticeable on white dials) along with the date being a bit sunken. Movement functions like a 7750 for date changes, meaning your date change starts somewhere around 10 o'clock and for about half an hour in 24 you'll have a half-date. Crown shanks need to get red-loctited because they like to unscrew inside the watch. Hands are sometimes too tight or too loose on the pinions, there could be some idiosyncrasies with painted rivets of black dial models, all models hour totalizer is fiddly due to gear train design - if it brushes on anything it will stop your chrono. Case lugs are too thick and some watches will have deeper strap notches than others due to low mfg. tolerances, lume is not superlume. Some models had incorrectly engraved casebacks but received a facelift along with hand rivets.
The below is just a guess, I don't have any special inside information.
The new updates will very likely include new crystals & a/r from the current mfg, new cases with adjustable hex crown tubes, better crownguards, possibly more streamlined lugs and overall better tolerances. Updated dials with the current "superlume" or superlume-like formula, relocated datewindow to the correct ETA7753 position, DW font bolder and printed further out on the DW to match the new window position on the dial. If you haven't noticed some of these changes are already in place with PAM326 and now more recently with updated PAM187.
