Ford’s 2015-2017 Mustang GT looks nearly identical year to year, but small changes in infotainment, suspension tuning, and paint colors separate one model year from the next. SYNC 2 gave way to SYNC 3, struts got re-valved for a smoother ride, and a handful of exclusive colors came and went — clues that can date a Mustang GT even when the sheet metal gives nothing away. Can you tell which year this yellow GT rolled off the line?