iPad Pro 12.9 1st gen LCD panel dimensions

I’m considering using an iPad screen for my hobby project, but I’m not sure if it will fit. I’m interested in the dimensions (just the width and height) of the panel itself, without the glass. I have a Pro 12.9" 3rd gen screen on hand, and it’s a bit too large for my project because of it’s 268mm width.

I’ve read somewhere that older generation panels are actually smaller (around 262mm wide, which would be perfect for me), but I can’t confirm this before getting one. Real 12.9 with 4:3 can't be that small but who knows if they was real 12.9 and not something close.

Could someone, by any chance, measure it?

I am not limited to 1st gen, if you have some other generation 12.9-13 screen - measurements are welcome :)