Parts for old style Truth casement window locks

This looks similar to the plastic piece in the back of the 38-144. Take a look and let me know what you think. If that's the same function that this part serves, then I'm afraid it's not available by itself. You would need to replace the lock by itself. If the 38-144 is not a match, please take a few pictures of the lock you currently have and we can try to find a better match.