The meaning of the balls is negative. In this same paragraph where the balls are mentioned, Lansing says “And what, incidentally, do you think integrity is? The ability not to pick a watch out of your neighbor’s pocket? No, it’s not as easy as that. If that were all, I’d say 95% of humanity were honest, upright men. Only, as you can see, they aren’t” (321) This shows Lansing has a negative opinion of most of humanity.
He goes on to say, “Integrity is the ability to stand by an idea. That presupposes the ability to think. Thinking is something one doesn’t BORROW OR PAWN” (321). This shows that Lansing thinks that most people do not think. Most people borrow or pawn ideas from others.
The cross, eagle, lion, and unicorn would be grand symbols, meaning perhaps sacrifice, freedom, bravery, or purity. Instead, humanity’s symbol is three gilded balls, a symbol of borrowing/pawning. Most humans are borrowers/pawners, not sacrificing, free, brave, or pure. This view is in line with Rand’s/Roark’s later words in this book about second-handers. Things in a pawn shop are second-hand. Howard Roark speaks poorly of second-handers. They are a negative thing, just like the pawn shop, just like the gilded balls.