It wasnt so much an option as a feature. And as a feature, it described the installed angle of the upper and lower control arms and spindle height. I believe it just means they built in more inherent caster to the geometry. It is a good configuration but MG and Mercedes had been doing that for years. And yes, a 72 LeSabre would have that feature.
So it looks like the front end on a B body needs less work than A bodies. I use Global West uppers with B body spindles on my skylark. That was the trick system 15 years ago.
yeah they are better set up as are the later a bodies in the 70s. rear is pretty similar all around. still could use improvements.