I remember GNX 223 very well....used to visit Dralle Buick in Peotone to drool when it was NEW. Have photos of it in the dealership. In 2001, I purchased a NOS GNX dash from GNX Guy ,who previously owned it. 223 was on Car and Driver segment with Joe talking about it. That GNX was also on display at the corvette museum.
You may give my info to the new owner