in the FWIW column, if the BF109 has the exhaust manifold low in the cowling, it's authentic. If it's high, it's post war Spanish built (under contract) with the RR Merlin engine.
A post-war Spanish Me109...
(http://farm1.static.flickr.com/6/8833452_9f2fcb21cf.jpg)
The WW2 German Me109...
(http://www.militaryaviation.eu/images/Messerschmitt/Me109_FM+BB.jpg)
The significant difference in the engines is that the Daimler-Benz V12 in the Me109 was inverted, and fuel injected. The Merlins in the Spits, Hurricanes, and F-51s were vertical and carburetored.
Just thought I'd throw this in.............