This may apply to other blocks, I've never noticed. The Warfare 2 DLC has three Bridge Window blocks - Two triangle variants, and one rectangle.

I built a "mock up" in my hanger to figure out the pieces. The bridge windows seemed to have a very specific alignment. It seemed that if I had the fat boarder down, and on the "inside", I could only have the window slopping out, so I had clear glass on the inside. Fair enough, and I was able build a simple wrap around example for myself.

I went up to the bridge I'm building on a ship and tried to recreate it. To my complete and utter amazement, the rectangle was now fat board down and inside, as it was, but now it only slopped inwards! Uh.... Okay? That's what I kinda wanted anyway? But the two triangle variants still seemed to be oriented the same way - fat boarder to the bottom, glass slopping outwards. I'm confused.

Could it be that I placed the glass down from the outside? Could that change the orientation somehow?

I have screenshots of both if it would help, I'd just need to figure out how to post them here.