Are you sure about that Steve? Only the one part number as far as I can see for the rubber, although the pedal itself is different in several respects; the brake pedal rubber is wider on the manual, but as far as I can see the throttle one is the same...
Absolutely certain! I've had a manual and auto one side by side for comparison The auto one is larger in both directions, only by a few mm, but it would be enough that a manual rubber wouldn't fit an auto pedal. I only checked because I have on hand 3 distinct types of pedal, 2 manual types, 1 with an "down" stop and 1 without, plus the auto type (I have 3 of these) all have the "down" stop. This is not definitive however as all 3 came from post 76 cars. I can't see that there's any positive advantage to the larger pedal for the auto and in my case, i'll be using the (presumably) earlier, stopless manual pedal on my auto car as it's going to be operating a throttle potentiometer rather than a cable and I don't want to limit it's travel in case I lose the kickdown or something!
BTW, it's the auto brake pedal that is wider, which I'm sure is what you meant to say!
PS, just looked in MY (1975) Sprint parts list and this too shows only 1 rubber for manual and auto, but includes a different manual pedal to ANY of those I have in stock! Mysteriouser and mysteriouser! Mayhap the larger pedal is a later than 75 thing?