Can anyone tell me if the fenders for the 51-52 F1 and F2 are different sizes?

 

The wheel opening is bigger for the F-2 than the F-1.Other than that the fender is the sma size.
The lower sections are also a slightly different
curve. You seem to find more of the F-2 fenders than F-1's. The F-1's of all years are more popular for purists and rodders.