Early 3800's were all shipped with stamped steel oil pans. All steel oil pans in front-wheel drive cars were largely the same. The rear-wheel drive cars (97-02 f-body's) were shipped with a slightly different oil pan with a drain plug located towards the rear of the engine.

Sometime around 2004 3800's in w-body's started to be equipped with aluminum oil pans. Typically the w-body will have an aluminum subframe if there is an aluminum oil pan as well.

3800 equipped Bonneville's may have recieved an aluminum oil pan as well at an earlier point (?)