The tail stock locking eyebolt rides on a cam on the locking shaft.
The cam is to the left of the eye bolt as I was in the process of assembly here. So as you rotate the shaft it raises / lowers the eyebolt that locks the tailstock.
This is the end of the tailstock with the locking shaft sticking out. I have an alignment punch in it right now. So depending on the orientation of that shaft when the locking lever is placed on it, will determine the direction you push / pull the lever to lock it on. The lever is attached with a tapper pin and a set screw, so most likely it will only go on in one orientation.