Bare steel dipped in semi-black paint on the pedal end
For some reason there are a few examples from early (first 6 months or so of production at Dearborn) where it appears the pedals were dipped further than later in the year and beyond. Very very early San Jose examples show them dipped to the "normal" depth
Might find a few examples in the unrestored picture section of the site
Others may have their observations from unrestored Aug 64 built Mustangs