Here's one for all of you Apollo owners or X-body guys. Not sure if you all have the same issue in identifying correct sport mirrors, like the A-body guys, but in my research of identifying sport mirrors for the GS I also came across the X-body variant. Here are some helpful identification tips in identifying the sport mirrors for the Apollo or just about any X-body car. I found that the major difference between the X-body mirror and the Skylark/GS mirror is the Base/Pedestal, Mounting bracket and gasket. According to my parts manuals the original assembly part numbers for the 71-75 X-body would be: Drivers Side = 9882068, Passenger Side: 9626974. The set is listed as 983406. These assemblies are easily identified by an "X" casted in the underside of the drivers side pedestal and an "O" casted in the underside of the passenger side pedestal as shown below. I see a lot of mirrors advertised as Camaro/Firebird or A-body with these casting letters where the seller has no idea what they have. So when looking at pictures or mirrors online look for those letters and you will be sure to have the correct ones for your X-body. The base/pedestal: The angle and length of the pedestal is unique for these cars: I found that the upper housing and mirror glass assembly is basically the same as the early A, F and G-body except that the drivers side remote cable is a couple of inches shorter on the X-body assemblies. The Gasket: The base gasket P/N is 9877665 for both drivers and passengers side mirrors and it an X-body only design. The bottom of the gasket is convex to fit in the channel of the door. Finally the Mounting Bracket: The typical Buick Skylark/GS (A-body or F-body) bracket tabs are angled whereas the X-body tabs are perpendicular to the door mounting also, the distance between mounting holes is shorter on the X-body: I've come across a few post 1975 X-body mirror sets with the same "X" and "O" casted letters so I believe this design carried on up into the 80's. Hope this helps!