I see more like 3/8" forward on the arms that I looked at (including an overlay tracing that I did on cardboard to compare them) . I think it really depends on the arms and how they were machined. I have seen them where the ball joint is centered in the boss on the casting and I have seen where it is machined all the way to the front of the boss.
I think they decided late in the game to add some caster and they did so by simply machining the ball joint hole on the extreme front of the boss which is about 3/8" forward. If you are at a junkyard you can probably pick and choose to eliminate this issue by choosing arms machined in the middle or back. Hopefully this was really done on purpose for caster and not simply tolerance at the factory...
On the charger I kept the stamped arms to save weight. If the tires clear on the given car then the extra caster is good (but I also have caster plates so that is mute on my setup).
The cast arms were really to reduce deflection on the heavy cars. That is why the caravan never came with stamped dual pivot arms. It is less of an issue on the smaller cars.
-Rich