[Nick Beale]

If it was a G-10 then the sixth digit of the Werk Nummer is missing.

As far as I know, the 770 series were G-10/R2 reconnaissance models and so if yours was in Italy it should have served with NAG 11. The unit was based at Udine-Campoformido from late 1944 through to the end of the war. There were several Bf 109 G's found on Italian airfields for which no details were recorded (often because they were too badly damaged to find any i/d), including five at Campoformido.

(770223 was delivered to NAG 3 in Luftflotte 6 in April 1945, so you can eliminate one aircraft from your enquiries, at least).