The badges on the side of the car are incorrect. In 1988, the Z28 badging on the car went away and all outside markings said IROC-Z. It was not a mid year change. The car was repainted and these badges were probably all that was available at the time. It's possible the badges were supposed to be red and those are next to impossible to find.
The 1985 thru 1987 IROC-Z said Z28 on the rocker panel. The 88-90 IROC-Z said IROC-Z on the rocker. The 91 and 92 Z28s went back to the Z28 badge.