The issue does not pertain to the part number. The part number consists of 10 or 11 digits. 
	I encountered a thread (not related to Mercedes) posing the same inquiry, and the sole pertinent reply received was, "those figures likely originate from the specific casting or production batch that manufactured those knuckles." 
	Thus, there is no conclusive response, although it is logical. 
	 
	This leads me to my initial inquiry. Is it possible to use any knuckle from different models such as w203, w209, c209, and r171, provided it is compatible with M10 bolts? Thank you for the link. I will examine it. I seek to verify my part number, however I am uncertain of its utility, to be honest.