Here's how it ended up. I removed one of the rubber bushings I made from the strut on one side and took the car to a Chevy dealer (one that had a much better service dept. than the one I had previously dealt with.) In effect they told me that the 1/2 inch gap at the top of the strut column is normal and there was no problem present. They gave it to me in writing on the work order release. Apparently this is the way the strut mount is designed.

I removed the rubber bushings that I had made to eliminate the gap on both struts. I'll wait until next year when the car is due for state inspection again. At least now I have some documentation with which to refute the decision of the state inspection agent, if anyone should make an issue of it in the future.