According from Japanese sources, the N1K2-Ja couldn't carry 4 250kg bombs under the wings.
It had only 4 60kg bombs, and the N1K2-Ja didn't use its loadout in the service.
The Kawanishi Kyofu carried a pair of 30kgs, the Shiden carried two 60kgs and Shiden Kai carried 2x 250kgs.
The N1K1-Jc Shiden Model 11C was rated to carry 2,204lbs of ords or 4x 250kg's, however I am not getting
any production numbers, so I can't say how many were produced.
The Ja model, did carry 4x 60kg bombs.