I haven't any information that would assist you other than the following information... the XF4U-5 first flew in April of 1946; that's a bit late for Okinawa.
According to "Warbird Tech Series, Volume 4, Vought F4U", and I'll quote:
"Beginning in January 1945, F4U-4Cs were produced with four 20mm cannon as standard armament. The first of these 300 aircraft reached Okinawa with Marine Air Group 31. Launched from the escort carriers Breton (CVE-23) and Sitkoh Bay (CVE-86), they flew ashore on L-Day plus seven (7 April) in time to intercept inbound kamikazes."
Another quote from the same source may be of interest: "The dash four probably had more variants than any Corsair model. Early on, the Royal Navy version was given the designation F4U-4B, but the war ended before the Fleet Air Arm aquired any such aircraft. Similarly, Goodyear was to have begun production of the equivalent FG-4."
I hope this information helps, sir.
Patches