They changed slightly. I think the pre 67 brake pedal had a different bend to clear the different placement of the steering column. I actually got a pre 67 set, and got a little hosed, because they would not fit. What I ended up doing was cut my auto brake pedal pad in half, and am going to use it that way.
Only other thing that I know of is that the bushing setup changed slightly through the years, and as far as this goes, I think they are all interchangeable and will work ok.