The breech blocks of German tank guns are often represented in green. This is because the examples in Bovington museum were painted green after capture. I believe this is British Army practice. But they were not this colour when in German service.
This is my incomplete model of the Tiger's breech. It shows the correct colours. The right hand side and the inside are unpainted, because paint would have fouled the moving parts. The top plate and the lugs for the travel-lock are also unpainted. The rest of the breech has the standard Ivory colour.
This breech had a falling block, controlled by levers on the right hand side. The large lug on the right attaches to the hydraulic buffer.
At the rear of the breech there was an identity plate. Early Tiger 1s had it at the lower right, as shown here. These plates were unpainted steel.
The left-hand lug on the breech was below the center line because the hydraulic recuperator attached to it had an off-center plunger. This lug also prevented the gun from twisting because it slid along a channel on the deflector guard. For this reason it was fitted with bronze shoes.
[2] Survey of Tiger 250122, at Bovington museum, by David Byrden
[3] German PzKw.IV TANK; Report on Examination of the Turret and Armament", Department of Tank Design, 1943 (Bovington Museum)
[4] Der Panzerkampfwagen VI und seine abarten, Walter J. Spielberger, Motor Buch Verlag