The Empire Strikes Back Boba Fett costume is often referred to as the Empire costume, or ESB costume.
This costume was painted in a very similar style to the First Prototype Boba Fett costume and the Third Prototype Boba Fett costume (and bears a striking resemblance to the Third Prototype Boba Fett costume) implying it was painted by Joe Johnston. Joe Johnston claims to have painted the First Prototype Boba Fett costume and it is unknown if he painted the Third Prototype Boba Fett costume and the Empire Strikes Back Boba Fett costume or if someone else tried to match Joes style of paint work.
As with the costume and armor, the Empire Strikes Back Boba Fett helmet is very similar is strikingly similar to the Third Prototype Boba Fett helmet, so much so that the Third Prototype Boba Fett helmet has been mistaken for the Empire Strikes Back Boba Fett helmet in the past.
While the Empire Strikes Back Boba Fett helmet stills exists and resides at the Lucasfilm archives when not on tour, several parts of the costume have been to have repainted for Return of the Jedi. For years there were rumors that this costume had been stolen, but it would appear that it was repurposed and is forever gone.
