DaveC,
There is a little difference, ...the ''F**k You'' is always given showing the back of your hand, while the Peace/Victory sign is showing the palm of the hand and the rest of your fingers!!
Also , normally the first is given with a nonchalant look on your face, and the second with a smile and or pride look on the face....
Small differences, but like many small things in life, ....the difference in meaning can be ''Huge''!!! ...haha!!!
David....