Yes, I had one with T-tops. It was dubbed by Ford as an '84 1/2 model (like the original '64 1/2 model) and was only a GT with GT 350 striping and a commemorative plaque. When announced they were going to produce the GT 350 Anniversary, they claimed it would have the '85 engine and dual exhaust set up but that never materialized.
I found this interested '84 GT-350 with only 212 actual miles that sold at Barrett-Jackson (Scottsdale) in January of 2019. Sold for $35,200. I'm mainly posting this info for those who had never heard of these GT-350s.
This 20th Anniversary Mustang GT350 has been stored its entire life and has 121 actual miles. This low-production Mustang is still in original condition with the interior still in the factory plastic wrapping. It boasts the Fox Body-generation's iconic 5.0-liter high-output V8 power plant, mated to a 5-speed manual transmission. The '84 GT350 was Ford's officially recognized Anniversary Mustang, honoring 20 years of Ford's finest moment, the Mustang. The anniversary cars were all finished in Oxford White with Canyon Red interior, and treated with the nostalgic lower rocker GT350 triple-red stripe, red body side moldings, Pony fender emblems and unique anniversary dash badge. The GT350 Anniversary cars were made in limited production, with a total of only 5,261 cars built. This included both coupes and convertibles and with both engine options, the 4-cylinder turbo and the 5.0-liter V8. The total production for the GT350 convertible with 5.0-liter high-output engine and 5-speed manual transmission was just 587 in total, with only 282 being convertibles. Options include power steering, power front disc brakes, Traction-Lok axle, front air dam with integrated fog lights, factory air conditioning, high-back sport seats, power convertible top and AM/FM cassette with additional power amp. Also included are the Marti Report and documentation.