Seiko has always been so called in-house manufacturer. Rolex was more like marketing company than manufacturer. All Rolex watches before 2004 are more or less made by others than Rolex.

Here is some facts:
Movements ( Aegler 2004 )
Crowns ( Boninchi 2000 )
Dials ( Beyeler 2000 )
Bracelets ( Gay Freres 1998 )
Cases ( Genex 1992 )