a B damper will fit a slant. But good luck finding a B/RB in a boneyard these days. It will stick out like 1.5 inches more though.
I dont think they get them wrong as all their production is highly (probably 100%) CNC automated. I think its user error in understanding how tight these need to fit. Snout shape/eccentricity of 50 year old crankshafts is probably all over the board too with prior balancer hammered on or installed dirty. If you hone out a balancer to fit, you may be defeating the design of the fit classification for harmonic transmission from crank to damper. Question: how does tooling sharpness affect CNC production? Is the cut/material measured or is the tool depth measured? I'm thinking the latter but there has to be a QC step to determine if the cut is accurate?