Hi Grzegorz,
I am familiar with the JaPo book...
ALL G-10's were made new, not from damaged, repaired, or older airframes. Also, not all damaged or defective 109's were repaired, nor were they upgraded to new versions. There were repair facilities...however the level or repair was most likely only enough to get it in the air.
DIANA had a repair facility, but those were only for airframes which were damaged while still in the hands of the manufacturer...such as problems during test flight, US attack on trains while in transport, etc.
Older G6 and G-14 airframes were not recycled into newer aircraft.
"Yellow 11" is the only example with evidence of an older tail new tail, and as all G-10's were made new, it was concluded that the modification done was most likely to get it into the air to the Neubiberg to surrender to the US and escape the Russians.
Field modification did include tail replacement, and repairs like that have been known to happen in the field quite regularly. If you have a damaged tail on an otherwise airworthy airplane, you install a good tail from an unairworthy aircraft. The tail attaches with 6 bolts if I remember correctly...so it is a very easy installation.
