It could be changed after it left the factory no-problem. Someone probably had it done because they were going to use it during a time that they would have something on their hand that the crown would hit or interfere with (such as heavy gloves, diving stuff, etc). To change the position from left to right you would only need to change the dial feet position (or cut off the dial feet and use dial dots to hold the dial on in its new position, which is the case for the conversions of other dive watches that I have seen before) and the calendar wheel (as the original date wheel would show upside down on the opposite side and not line up with the window).