larry wrote:

Also I recall seeing photos of Columbia when it was being readied
for flight. The Panels were black not the gray of the test panels.

I believe you recall incorrectly. Here's a link to a
launch photo of a relatively recent shuttle launch
(Endeavour, STS100, April 2001)

http://spaceflight.nasa.gov/gallery/...01pp-0832.html

Click on the low res(*) link, and look at the leading edge
of the wing (near the USofA flag), and the shuttle's nosecap.
Both are medium dark gray, the same as the RCC panels used
in yesterday's test.

Perhaps you are confusing the black tiles with the RCC panels?

(*) -- or the high res link...