LOL - I love a good challenge!
After LEFSA posted that the person she talked with at KA-USA said that 4KSM50PWH was a serial number - I knew that the person she spoke with didn't know about model numbers from KA-CANADA. Probably since KA-USA model numbers do not start with a number .... but some older serial numbers did, like the old K5 mixers - the serial numbers began with 3B.
Another clue was that most KA-USA model numbers begin with "K", most KA-CANADA model numbers begin with "4K". And, if you go to the KA manual site and look up K/4K numbers you'll usually get a hit of some kind ... but if you search on a serial number you get nothing. And, if you search on a 4K number and don't get a hit - removing the 4 prefix will usually get you a hit.
So ... this afternoon (3:30pm CDT) I called the Whirlpool/KA-CANADA support number (800-807-6777) and talked with a young lady named Nancy and got the straight story on that mysterious "4" prefix. It is a unique number used by Whirlpool/KA-CANADA for an engineering code to signify that there is something that conforms to some specific Canadian product code requirement - like in the US one of the requirements would be to conform to UL standards - Canada has their equivalent to the UL. It doesn't signify anything physically different - just that it conforms to a different standard in some way.
So - it breaks down this way .... the only difference between a 4KSM50PWH (Canadian) and a KSM50PWH (USA) mixer is basically the manual (the parts are the same in both machines). The Canadian manual will have information for contacting KA-CANADA support instead of KA-USA, ingredients are listed in both standard and metric, and part numbers (like in the accessories at the back of the manual) will be KA-Canada numbers instead of KA-USA numbers (such as 4JE instead of JE for the juicer).
So, the link to the manual I posted before for the KSM50PWH is valid for the 4KSM50PWH as far as operation ... Saphellae will just have to convert standard measurements to metric ... and check the KA-CANADA website for KA-CANADA for replacement part or attachment numbers.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain