Yep, we're finding the roundabout way to describe the upgrades from TL-2 to TL-3. Obviously, my TL-2's have plunger ejectors on the bolthead and your TL-3 has it on the rear/side (assuming left side, for a RBRP) of the action.
Whodathunkit ? Have never seen a headspace gauge with a plunger relief. No, wait a minute, my .223 gauges have them. (Sheepish grin......) I hadn't put 2 and 2 together......So that's what they're for....