DSMs were actually built in Normal, IL and all the sheetmetal probably came from Detroit. In fact, if I remember correctly, Dave Buschur, DSMs biggest celebrity at one time, use to work at the plants that pressed the metal into shape.
Except the motor, tranny and 90% of everything else came from Japan and Mitsubishi. And in just about every book it is considered an import.
I'm 2point4 on PhillyDSM.