B5N has ventral gunner?

[pandacat]

I usually go low 6 approach against bombers like D3A or Ju87 cuz their gunners can't shoot low. But last nite, I was using the same approach against some B5ns. I was surprised to see a shower of bullets coming my way even thought I was right underneath them. When did they get ventral gunner?
I thought TBF is the only single engine torpedo bomber has ventral gunner.