Hot Rods Model A windshields?

...are all Model A windshields the same for coupes , sedans, and pickups?...are 28-9's different from 30-31's...

 

Yes, 28-29 and 30-31 are different.

 

...are 28-9's narrower than 30-31's?

 

No they are all the same width and you can make them work with a little wittling and adjusting. 28 29 are different from 30 31's but they can all be made to fit with a little work.

 

Top hinge is different...

 

Roadster is . Making a 28 from a 30 with rusted corners. But I'm not sure about closed car.

 

Bratton's and Snyder's each list several variations of windshield frames.
Their descriptions don't specify dimensions, only years and models.