I agree that the shape of the head does not look correct for a Buick. Also, I have never seen a centurion that came with sport mirrors. There may have been some but I never remember seeing one.
no sport mirrors on the Centurion, but they can be added. 72Rivguy here on the board has them on his Centurion: http://www.buickcenturion.com/1972/carl_s/
I got a set from a 83 regal, they look pretty sporty, will go on at some point in the distant future.
Buick offered the sport mirrors as options on the big Buicks starting in 74. if you have access to a wrecking yard that has older stuff, then a set of sport mirrors from a 74-76 big GM car should work just as well. Mine came from a 76 Riviera.
