Replacement "keeper?"

Hello: I am somehow missing one of the plastic parts I am providing pictures of. This is for a left-swing casement window, and is the part that attaches to the window itself and engages the latching/locking arm to close the window. It's 1 3/4" long by 5/8" wide by 9/16" deep and is a hard, white plastic. It you have this part of something similar that you think would work, please advise. Thank you!