Thanks! I didn't know they were different (4 spd vs AT) until I was at a swap meet last year. A machine shop guy who builds 351Ws showed me that the AT driver's side manifold opens directly rearward (as in your excellent photo), while the 4 spd manifold tilts slightly downward. He had a set to sell, but at the time I didn't need them (of course). I am going to my shop this afternoon, and I am going to try and see if I can see the numbers on my original 4 spd coupe, but this car is what you expect to see after 40 years and 300,000 or so miles, so I may no be able to read anything.
BTW, this site is great! I may not have anything even close to concours, but that doesn't mean that I don't want them to be as correct as possible for someone of my, ah, talent (or lack of). Thanks again.