Here are three harmonicas that Sonny Terry actually played. With Adam Gussow of Modern Blues Harmonica.
Gussow starts with an A harp in Fair condition. Then a C# harp in Good condition. (NOT a Db. This was a much rarer C#, with "C#" stamped on the coverplate.) Then a pre-war Bb harp in near-mint condition.
Gussow was retained by the executor of the Sonny Terry Estate to assess the condition of Terry's entire surviving stock of harmonicas. These include many Hohner Marine Bands and Golden Melodies, along with a scattering of other models. At some point in the future, a number of these harmonicas will be offered for sale to the general public, accompanied by certificates of authenticity.