Window Latch

We recently order some spiral balances from you for our windows. While replacing them we found that some of the windows are missing the latch that hooks into the plastic part in the window track below the spiral balance. In picture 1, you will see the metal lever (part with the screw in it)that sticks out further than the window, that part is missing in picture number 2. Do you know if you carry these parts or something similar that we could use?