I dunno. I expect those rails were furnace-blasted and quenched as they rolled-out?

The surface of the one at my shop is not hardened and I like it that way for pinning.
Harder than nickel silver, brass, and bronze pins I use.
Once a year or 2, I take a Jitterbug and some 100 to it.
The buggers stick and don't scoot as I pin...Just me.