Well, I went straight to the source and asked Mary Brace (George's daughter) what the deal is with the Rowe postcards and she told me that Rowe and Brace were good friends and traveled together to Cooperstown and Spring Training and they both belonged to a group called the "Hit and Pitch Club". Brace allowed Rowe to use his negatives and any profit made was Jim's to keep with the understanding that the negatives would return to Brace if something happened to Jim...Jim moved to Florida and George lost track of him...When Jim died there was no provisions made for the negatives to return to the Brace family.
Btw Mary still sells her father's photos at this website:
http://www.bracephoto.com/