Hello Massimo
I only saw these images showing this detail clearly. As also Aviarestoration placed the trim tab accordingly, I thought that the "wrong" drawings came from a prototype feature. But, looking at the I-200 page (
http://mig3.sovietwarplanes.com/mig3/I-200.html ), the drawing shows the tab in the "correct" place, and also the pictures seem to confirm this. Therefore, I think it is an old mistake's legacy.
I must say that, building this model, I found the MiG-3 far more enigmatic and complex than I expected
.