The Super Shifter Three I had in a 1968 Baracuda in 1974 or 1975 didn't have that lever, I think I needed to push the shifter lever straight down in neutral and then move the shifter handle into reverse to the left and up towards the motor shruggy
I think the Hurst Ram Rod shifters and some of the Mr. Gasket shifters had push down or pull up levers like that for reverse, maybe not confused

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)