ID '60-'62 POwer Brake Booster Adapter Bracket With A Clutch

[bhap]

Hey CaptainFab, I'm finally getting around to installing your power brake booster bracket and have a quick install question. On the clutch bracket that mounts on the inside of the firewall there are two hex shaped spacers welded to the bracket, one is threaded, the other is not. At the tip of the spacers there are small "nubs" - one on each spacer. What is the purpose of these nubs? Do I just tighten the mounting bolts and pull them into the metal on the firewall? I'll attach a couple of pictures so you can see what I'm talking about. Thanks for your help - this is definitely a well made piece!