I just went through the Gutman's book and I couldn't find a photo of Booth wearing a double breasted frock coat. I think this style here appears to have been a favorite of his and he was photographed in it several times. I'd say the type of shirt Rick found with a simple cravat and a coat like this would be close.
"There are few subjects that ignite more casual, uninformed bigotry and condescension from elites in this nation more than Dixie - Jonah Goldberg"