These springs are on a 70 Torino formal with a 351 c and auto trans, San Jose car. Rear springs show runs which shows how they were hung when marked.
Since the springs were provided bu the same suppliers as most of the other Ford products I believe the springs were painted with a brush while laying on a table or floor upside down from how they were installed. This would still provide the downward angle that would produce the run we see in your example. Its not unusual for the paint to still be wet (not completely dried) when they moved the springs after so you can find some unusual - not normal effects from that also. Also consider that painting by hand while a spring is hanging is much more difficult and slower than if they are all laid out where someone could apply all of one color down the line then repeat or have another worker applying the next color
Front spring also shows a run, must have been on it's side.
Think that run at the base is a result of the movement of the spring after it was painted. IMHO we can;t look at one example and draw good conclusions but instead look at, lets say 100 examples, and draw conclusions from the group. Just a thought
Thanks for posting - hope this goes to help someone else. You might want to include more info from the car so that others will know if these possibly apply to their car or not. For the rear springs the markings/stamping info would likely be the most help