Here is a photo that used to hang in the shop that was sent from Rafael Mendez to Carroll Purviance. Purviance made him a 6C3 model that he refers to in the signed note. Mendez came by Bob’s shop in Hollywood and would bring his friends and students.
The writing in the lower left is hard to make out in the scan but reads:
“Para mi amigo Carroll, [To my friend Carroll]
Thanks for the big improvement that your wonderful mouthpiece made in my playing.
Rafael A. Méndez
Click on the photo to see a larger version.