The Chassis Code for the 1990-96 Pontiac Trans Sport/Oldsmobile Silhouette and Chevrolet Lumina APV is [GMT199]. For the 1997-2005 Chevrolet Venture, 1997-04 Oldsmobile Silhouette, and the 1997-99 Pontiac Trans Sport & 1999-05 Pontiac Montana, the chassis code is [GMT200]

https://en.wikipedia.org/wiki/GM_U_platform