E7te 13 & 14 = Left And Right?

[fords2live]

On the top of my E7s one head says 13 and the other says 14. Does this mean passenger and driver side? Why is there a difference?

 

[Noobz347]

Look for the open smog ports. Those go in the rear.

 

[7991LXnSHO]

Once on the car, blocked ports are a pain if they are on the wrong end. If you wish to block them, please use a bolt. No idea on the numbers.