Here's a link: http://www.northeast.railfan.net/bo1.html Look for numbers 4128-37 from 1971. FA2s are one of my favorites - especially in the first paint scheme.
Well, lets see here. There were four A-B-A sets, and one A-B-B-A set that were set up with steam generators for a total of 10 A units and 6 B units. The A-B-A sets were numbered 809, 811, 813, and 815. The A-B-B-A set was numbered 817. These were actually FPA-2s and FPB-2s (P for passenger). B&O classified these as class DF-7 and DF-7x. The FA2s are one of my favorites - especially in the original blue, gray, and black paint scheme.
Thank you Tim, I am trying to update the Wikipedia page. Richard Steinheimer has the quantity as 10 As and 5 Bs in his Centennial Remembrance Book, that is where I got the quantities from. I am sure you are using a different source.