Starting in mid-April and running through the late 1990 model year, Ford placed 25th anniversary, tri-bar pony badges on the passenger side dash of all LX and GT Mustangs. The called it the 25th Anniversary Mustang but since the changes applied to all cars it was hardly a special edition model.
To celebrate the Mustang’s 25th anniversary, all Mustangs manufactured between April 17, 1989 and April 17, 1990 received a dash plaque decorated with a galloping pony badge, the three tribars and 25th anniversary stamped at its bottom. They also had a window sticker/invoice with a running pony and tri-bar logo and “25 Years” watermark.
After April 1990, the badge on the dash was changed to just the running pony and the tribar without the 25th anniversary stamp. These are anniversary edition Mustangs, regardless of what some people say. Some people claim that there were only two anniversary editions up to this time, the 20th Anniversary Edition ’84 G.T.350 (5,260 built) and the 35th Anniversary Limited Edition ’99 GT when ordered with option 54Y. However, although these two years were “limited production” editions, that fact that FORD placed a special plaque on the dash for a limited time to differentiate these cars from others in these two years attests to their being somewhat special.