The serial numbers are based on year and week produced. Thus '10' reflects the 10th week of production, rather than a newer revision. The newer MacBooks, however, appear to solve many of the problems that have shown up in early production models. "Apple said that revision D MacBook Pros have many issues addressed and improvements made, including fixes to the above mentioned issues. We were also able to get a hold of a MacBook Pro that just arrived during the week with a serial number starting with W8612, which did not exhibit any of the above issues." Other users have also complained about a whining noise when the screen brightness is adjusted, which the report said is "fixed by launching a widget or by using PhotoBooth -- oddly enough this solves the problem until the next reboot." It is unclear whether Apple is offering to replace or update MacBooks Pros that exhibit the aforementioned issues, but it is important to note that all early models do not exhibit some or all of the problems. Apple is offering new MacBook Pros with 24-hour delivery time from the Apple Store as well as a slew of refurbished MacBook Pros. Other internet retailers such as Amazon also have stock of the new Intel-based laptops, with Amazon currently offering a $150 rebate. Update: The story has been updated to reflect that serial number scheme was not based on revisions themselves, but on the production week of the unit. There, however, still may be underlying revisions to the logic board that are simply not reflected in the serial number, but as production evolves.