Hi Michael,
One of the
Stab J.G. 54 aircraft was damaged at Riga, so it was definitely not involved. A quick check of this forum shows that the 14 February 1943 combat has been discussed before, and the son of the Sergey Semenovich Ryabushkin contacted me a couple of years ago about it. Conclusions then were the same as above.
Cheers,
Andrew A.
Air War Publications -
www.airwarpublications.com