2 different coding ?

[ARTESH]

Can someone explain to me why there are 2 different Coding on this one? Yellow 27 and bar and Black "BJ ?Z, i mean these.

 

[Airframes]

I'm not totally sure, but this is a Buchon, based at Usedom, representing an aircraft from a WW2 training unit, and I'm guessing the black code letters are the original factory call sign I.D., with the training unit code numbers painted over them in yellow.
This was fairly common in Luftwaffe training units, especially towards the end of the war in Europe.

 

[Wurger]

Yes I agree. The Hispano Aviation HA-1112 M1L Buchon pretends the Bf 109G-12 two-seat trainer belonged to the JG 101 fighter training unit, Germany 1944/45. The origin kite was G-6 variant initially and then converted into the G-12. It can be noticed that she is still wearing the factory uniform with the yellow number and band applied in the unit.

the source: Messerschmitt Bf-109G-12

And here an interesting link: Two-Seat 'Messerschmitt Bf-109' Will Fly Soon!

 

[Wurger]

And here two shots more...

the source: Messerschmitt Bf 109 G-12 JG101 2 seat trainer 1944

 

[Crimea_River]

The black factory codes are known as Stammkennzeichen. The LEMB Stammkennzeichen Database