Hallo Marc,
for your III./JG 4 query: Bf 109 K-4 W.Nr. 334 ..., III./JG 4, Jüterbog-Damm (?), March 1945. Source: eBay auction via Facebook.com.
https://www.flickr.com/photos/280920...7640118646745/
I have what I believe is the original handwriting on the back of the photo – Drewitz?
http://forum.12oclockhigh.net/showth...hlight=drewitz
Regards,
Sinisa