Anderson window casement operator 7198-17

I need to replace the operator for both left & right anderson casement window. The strait arm operator looks correct. However, it has a different part number.

On the back of my operator it is stamped:Does this make a difference?

I purchased new (39-150 and 39-150) arms that only open the window half way and then fall out of the channel on the window. There is an open spot on the channel of the window that allows the arm to become disengaged from the channel. The new openers are exact as the old ones except the part that engages in the channel of the windows.