Saxman that is a great question,
Unfortunately Grumman had so many problems with the airspeed indicator in the F6F I don't think there is anyway anyone can know how fast the F6F was actually flying.
Even in later models and in test run by modern pilots the results are so scattered there is no way to know for sure. I have copies of Vought test where they used radio towers to calibrate the airspeed and they could say with little doubt how fast or slow their aircraft was flying. Then I have no less than 4 seperate CAS charts for the F6F some of which having as much as 18knots of error on the high and low end of the speed range.
I believe the F6F would have been marginally better with no flaps and not as good with flaps in terms of turning circle.