Here's the drawing from the Ford Restoration Manual of the 28-29 Roadster, it is different than the 30-31 Roadster, I'll get that drawing for you as well.
Drawing of the 30-31 Roadster. A lot of people thought the 4 years of the Model A were identical, But in reality, the 28-29 were one style, and the 30-31 another, there are differences between the two. I'm sure it's caused some headaches somewhere along the line.