Honda ARX1200T3DXT3 Owner's Manual page 249

The hull identification number (HIN) (2) is
located on the hull at the rear of the PWC.
REAR
(2)
(2) hull identification number (HIN)
Vehicle Identification
The engine number (3) is stamped on the top
of the oil tank.
UNDER FRONT SEAT
(3)
(3) engine number
Technical Information
241