Hello. I was looking at some pictures of JBL 4310 thinking about getting a pair. I have noticed MOST of the 4310 have the foilcal on the front that reads "JBL MODEL 4310 CONTROL MONITOR. I have seen a few though that only have JBL CONTROL MONITOR, but are 4310. I was wondering if anyone knew if the control monitor foilcals had any lead to the age of 4310.