The nebberhood mechanic thinks that the Chebby dealer put a carb made for a 4-banger on the 6-banger he installed back in 1996. I guess it's too late to make a warranty claim! Anyhoo, I hadn't noticed since the truck was driven mebby 100 miles in the last 10 years. An incorrect carb would explain why the truck idles a bit oddly at times. But, it is usable for now.
Cost so far to get the truck moving: $4000.00.
I'll have a better picture later. I'm not Photoshop qualified yet!