There are actually a lot of differences between early 28 Standard Coupe bodies and 29 Coupe bodies (not talking about Special Coupes.) There are differences in the subframe, the rear wheel wells, the doors, and all of the floor pans.
Steve,The 1928 has three threaded holes in the lower left rear for the tail light. The 1929 does not. That is the only real difference between those two bodies
Steve,
My June '29 Coupe HAS those holes???
Bill W.