The RV-6A is a legitimate warbird by the rules. The Nigerian airforce used them. (WoA doesn't require your plane to actually have been owned by a military, just the same model, a lot of the L-17's out there never were owned by the military).

We'll park old homebuilts in Vintage if you insist provided they were actually built before the end of 1970 (for classics) or 1945 (for antiques). Occassionally someone slips in a "looks like that old" recent built in there, but according to the actual rules they are ineligible (only those that can be legitimately judged in our categories).