I would say that the Mk1 Vectra ran from 1995 to 2002 and is referred to as the Vectra B. This came in pre-facelift from 1995 to 1999. The model was facelifted in 1999 and ran to 2002. The change over came in 2002 with the launch of the Mk2 being the Vectra C. This has also be facelifted now.
The facelifted Vectra B had different headlights, rear lights, front and rear bumbers, dash detail, seats, new range of engines.
The bumpers are interchangeable between facelift and pre-facelift.
And just to confuse matters more, the 'official' Mk1 Vectra was the Cavalier, being known as the Vectra A in Europe.
:roll: