OK without disassembling my Classic I took a quick look at the bolt hole center line to the mounting plate inner surface ( where you are rubbing) the two center lines are not the same. about 7/8 of a inch for the standard and about 1 inch for the Classic. This would explain why I never seen a standard floor board kitted bike with a Classic brake pedal.
below is a modified picture of yours with the center line measurement identified that I am referring to and were talking back shoulder of the welded mounting bracket on the left not the outside diameter of the pedal pivot.
I used a 6 inch scale