I have got 4 pairs of black painted or phosphorized ones. Two with, the other 2 without numbers. Well, actually I only saw numbers on one in each of the many times overpainted, or rusty and greasy pair. I've also got 2 pairs nickeled unmarked. That doesn't mean there can't be nickeled ones with marks. But I can't see any indentations that you are talking about.

Use the ones with less wear.

Remember to mount them right or you are getting trouble fitting the wheel, they are left and right sided. The short shaft bushing protrution against the fork, the long protrution toward the wheel.