The center bead is one of the few molding planes that has no integral
fence. The only way to use it is to use a board, clamped on the stock as a
guide, or to get out your plow plane, pull off the fence, arms and nuts and
replace them on the center bead, thru the holes you have bored more or less
in the right place.
Since centerbeads are bored about 40% of the time, and other planes rarely,
I think we can rule out the hang hole argument, unless somebody can think
of a compelling reason why centerbeads had to be hung up, whereas nothing
else ever did.

Ted kinsey