I guy i work with is selling his 91 z28 convertible. the car is white with black stripes with new black top. The car has a black interior with front seats front from a 4th gen. 91 was the year first year for the z28 to return as the top of the line model. only 3203 convetible z28 were made that year. http://www.teufert.net/camaro/1991.htm
I am sure that if you broke it down to find out how many white with black stripe z28 convertibles were made in 1991 you would find this to be an ultra rare car.

 

your friend ever sell this car?