My 91 300D is a Canadian version and it has electronic seat adjustment. I think it was an option, electronic and heated seats, along with the pass. side airbag. Those were listed on the original order form for the car.

__________________
1991 MB 300D 2.5 Turbo (207000km) (now gone)
1993 Audi 100 CS Quattro (300000km)
1999 VW Jetta TDI (290000km)
2002 Audi A6 3.0 Quattro (150000km)
2005 MB E320 CDI (34000km)