| Fil2,
Just been through the Ducati parts catalogue. Part numbers for all the exhaust parts are the same for MY00, MY01 & MY02 which makes them all 45mm.
Sounds like someone has fitted a 45-50mm half system - unless you're the first owner in which case speak to the dealer and see if they fitted it.
Are you talking about carbon or Ti cans or are they standard aluminium ones? | 
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