Charlie,
I love these types of sets also. Interestingly, the photos used in the Pictures of Champions set are the same photos from the Mike Andersen postcard set. It leads me to wonder if Andersen was involved in the printing of the set or just let them use his photos.
There are 29 Mike Andersen Orioles postcards, but no Boog Powell. Maybe Boog wouldn't allow Andersen to use his photo. Thus no Powell in the Pictures of Champions set. The Andersen postcards are really nice quality, but very tough to find. I'm still missing the Brooks Robinson and second pose of Frank Robinson.
Here's the postcards I have
1969 Mike Andersen 01.JPG 1969 Mike Andersen 02.JPG
1969 Mike Andersen 03.JPG 1969 Mike Andersen 04.JPG
1969 Mike Andersen 05.JPG 1969 Mike Andersen 06.JPG
1969 Mike Andersen 07.JPG 1969 Mike Andersen 08.JPG