The skin thickness of the A6M was generally 0.032" with some 0.025" (more then a little) and some 0.020".
Thanks for the real life data, I'm speculating its perhaps a 0.025" +/- specification. The only reference I've found said that from March 1944 the A6M5a Zero got 0.2mm thicker wing skin this is ~0.008" extra which would bring it to 0.033" +/-, this was claimed to increase dive speed from 414 -> 460mph.