Hitech said the era splits are:
beginning to mid-42: early war
mid-42 to early 44: mid war
early 44 to end: late war
F4U-1 and F6F-5 belong in mid and late respectively, based on historical appearance in combat. However, an F6F-3 would go in mid-war, but we don't have one, so I'm thinking they just substituted. Unless the splits change, I'd say the breakdown of aircraft in each era is correct--except for whatever substitutions they made...There's a similar thread on the P-47--folks wanting to see one in the early war. No jug saw combat before early '43, so no jug in early.
My two cents...