What is lockout for the reverse gear on a 71-72 E body and does it even possess it? Does this linkage prevent you from accidently shifting into reverse while going forward?

Reverse lock out is generally a function of the shifter reguiring you to push a button or move the shifter to a specific point in order to move the shifter from nuetral to reverse.

Yes your car should have it. What kind of shifter does it have?

It's a factory Hurst pistol car A 833. It's a early build 72 Challenger, August 71. I had a problem with the adjusting button that connects the rod to the lever. The threads in the button were gone so I tacked it to the rod.Now it keeps binding up and getting stuck in reverse. This is a temporary fix and in my limited knowledge on this subject I only see the reverse button lockout style not regular, like 1-2 & 3-4 buttons.Will the lockout button function properly if you dont have the lockout? I thought lockout was 70 only?

lock out mechanism is 70 only ,if OEM