Dan,
Thanks for the help. One of the posts shows a rubber seal on the bottom metal channel. After looking at it, I think it is there just to keep water out of the metal channel. It does not look like it would stop water from running by the glass and into the door. Also, I couldn't find a Model A parts source that sold that seal.
Since 28/29 closed cab doors are the same as 26/27 T coupes, I did find glass setting rubber that has a sealing lip at Langs. They also sell the metal channel for a lot less than the ones being sold by most Model A parts sources.