I found a hatch glass out of 75 280Z. Fits good.

The changeover date to horizontal defroster grid was 1/72. My 72 (SilverBullet240Z) had a production date of 10/71 and had a vertical defroster grid. The last month of production that used vertical grids was 12/71. The 72 model production began, I believe, in Aug 71.