Here's some great info via David E. Brown over on Hyperscale:
"A very good article about this aircraft was published by Steve Blake and Steve Sheflin in Sheflin’s “Airfoil” magazine that included photos from his and Jim Crow’s collections, two of which are in colour (“The Case of the ‘Stolen’ Fw 190!”, Airfoil, Vol.1, No.2, Spring 1984, pp.30-31.)
Red 31 + ~ is certainly an A-6 that was given a new power-egg, canopy and A-8 wings to create this recycled hybrid. The designation stays with the fuselage and so it would be nice to get confirmation via a good view of the tail and get a Werknummer.
Camouflage is rather mixed given its hybrid status. The wings appear to be in the standard 74/75 greys as is the fuselage back to the tail unit. The tail is certainly a replacement was a base coat of a lightened version of 76 with a mottle of 83 dark green. These tails are seen on a number of Fw 190 F-8s that were themselves recycled aircraft from older and/or damaged types. The power egg and forward gun panel appear to be overall 83 as seen in the colour shots. There might be a bit of 83 applied here and there in an attempt to unify the overall scheme.
The aircraft invariably came from I./EKG(J) - Ergängzungkampfgeschwader (Jagd) / reserve or replacement training bomber wing (fighter) and was originally stationed at Pilsen, Czechoslovakia. From there, it was invariably flown to the west ahead of the Russian advance, being abandoned at Linz, Austria where Carr found it.
The use of such a hybrid kite makes perfect sense for the unit and period of the war. I had pegged that Red 31 was an EKG(J) aircraft about ten years ago while studying an Fw 190 D-9 with a similar code and markings (“Red 18 + ~”, WNr.211115 found at Pilsen in May 1945). Indeed, the fact that there were many aircraft types associated with the unit was an immediate tip-off that this was a rag-tag unit that grabbed whatever aircraft they could and got them into operational status."
David E. Brown
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And, here's a bit of "semi-official" Urban Legend:
http://www.afa.org/magazine/valor/0295valor.asp
Wade