1385472 looks more like what we'd expect - the odd number on the back must be down to just the legends on the keycaps!
I haven't heard of any having an XT connector on, but others have far more encyclopedic knowledge than me. The cables are interchangable though. Usually they have this plug, which has wider spaced pins...
Show Image
(http://upload.wikimedia.org/wikipedia/commons/thumb/b/ba/DIN-5c_Diagram.svg/60px-DIN-5c_Diagram.svg.png)
But if he got the AT to PS/2 adapter onto the cable, the pins wouldn't have been spaced farther.
Strange, for sure. But IBM makes so many products with subtle variation that it's sort of expected.