Matching the Rooks' jackets? Yes, easily done. Iron oxide is incredibly easy to come by with all this metal around.
Small picture: bring it by the workshop at your earliest convenience - I'll borrow it for a few hours to make sure it's in good working order and make note of improvements I might make for Signor Auditore's new oen.
Big picture: private communication is easily done. How long distance do you want it to be usable for and how portable must it be?