Steve:

Since the Womacks card was coming to us through a broker at the time, any speculation is just that - speculation.

Going off of memory here - I believe the white one was their first one, with the yellow next (I don't know who manufactured the yellow ones), with the gold ones replacing the yellow. I recall hearing grumbling about how the white ones didn't reflect their idea of a "gold card". Many manufacturers do not stock gold plastic or ink, so they may have recommended yellow as a close approximation (gold plastic/gold ink costs much more).

Scott