They were too big to just post, but heres the data. It says nothing about being T-Tops, but it does say that its a special dealer order and I've heard of convertibles with 350s that don't have any RPO/VIN codes for the convertible so maybe this is the same.

http://www.geocities.com/casenjoe/VIN.jpg
http://www.geocities.com/casenjoe/Z28.jpg
http://www.geocities.com/casenjoe/hood.jpg
http://www.geocities.com/casenjoe/RPO.jpg