No, they are not. I'm not an expert, but I do know they are different. I believe the main differences are the skirt are that goes under the dash rail, and the hinge on top. That being said, they may fit between years by swapping the hinges on top and grinding the skirt to eliminate interference.
I used a 28-9 windshield frame on my 30 but I had to change the upper hinge. There may be other differences but it does work.