Any of those marks are OK for initial timing - to get your truck started.
If you know that the flywheel you have is the original one - use the ball (the "bb" embedded in the flywheel). Different years/engine had timing marks in different places - flywheels got moved around over the past 50+ years.
In any case the timing ball/marks were set for the gasoline for the day, and an average altitude.
Using a vacuum gauge (adjust to maximum vacuum at idle) is as good, or usually better, than using a timing mark/ball. Attach the vacuum gauge to the vacuum port on the intake manifold.
