4704-100 (50-key) bar foot has the following measurements
from edge to far edge of center support: 131.0mm
width of center support: 1.80 mm
Full length: 260.2 mm
diameter of "peg" 4.70 mm
Length from edge to edge of "peg" 40.55 mm
Length from edge to center of "peg" 38.2 mm
Width: 15.0 mm
I broke the foot getting it out (old plastic is brittle) but was able to measure it fine. It's symmetric. Let me know of anything else you need measured.