According to the experts per the tech. articles, the foil side goes up and is exposed to view. I have been following the restoration of a fifties Chevy at Chevy Duty's showroom and they installed the foil side up. Also, the tech. article in Classic Truck magazine shows the foil side up. Maybe it is the same concept as insulating a house, the foil side or kraft paper side is to the inside of the house. I have done the interior of my '66, C-10 cab with the foil-face insulation you are talking about (from Chevy Duty)and put the foil side up so you can see it.
What did you use instead of Dynamat? I'm sure others will chime in for a few more opinions. Good luck with your project.
