SIK,
That is a 251st Kokutai A6M3 Model 22 flown by Sakai's friend Hiroyoshi Nishizawa in 1943. Sakai had already been wounded and sent back to Japan 10 months earlier.
The Tainan Kokutai had been renamed the 251st Kokutai by this time. I believe that skin is in the game as well flying on the A6M3 Model 32 even though the actual aircraft was a model 22.