As usual Brad is right on the the money. So the sheet over the gas tank or the one most likely rolled up and inserted in the driver's A pillar is the only way to really tell if it was offered as a GSX optioned car. The daily car reports from Buick for that year do not cross reference the GSX options to car color, but I have seen at least one that was code 75, Fire Red, so they did make them. Unfortunately, the 71 model year records have never turned up so that is the technical reason for 71 cars, in general, we must have the individual car paperwork to authenticate how it was originally sold. Also, not to confuse the issue but in 71 what were packaged GSX features in 70 were sold by the piece. So, unlike the 70 model year, in 71 it could be correct without a hood tach or even with a vinyl roof. Jim Lore