Throttle Assembly

Have just been refitting the throttle assembly to the handlebar on my D125 MkII and notice that on the handlebar directly in line with the long axial slot there is a hole about 1" away from the end of the slot. Have saved all the items when I stripped the throttle and there is nothing there to fit in the hole. It looks like the hole has been tapped to accept some sort of grub screw - but for what purpose ? (The same hole appears on the gearchange side of the handlebar). Was it used to hold the outer of the throttle cable ? I am assuming that the throttle cable outer butts up against the carburettor arm at one end and the brass inner cable fixing at the other. Anybody got any ideas ?