Jim,
Thank you for sharing the Mustang Hardware spreadsheets - they're quite handy and shows a lot of work went into them.
I noticed the '65s had a count of 28 flat stamped nuts but '66 had 20. I didn't think the '65s had more unless they double nutted the baffles?
At any rate, it seems the going rate for air extractor assemblies on Craigslist in California is $500 for beat up incomplete units - ouch.