I bought my XLT Sport 11/29 and just had the dealer's body shop do the spray-in liner Friday. I added this at time of sale after seeing a Ranger they did on the showroom floor. Also added a Westin rubber mat.
I bought a 2012 F150 Ecoboost and remember that a front license plate holder on the Ecoboost f150s was offset to not block air to the intercooler. The non-Ecoboost trucks had them in the center. I wonder if that is the reason.
My XLT Sport has 4. Page 212 of the owners manual shows a picture with 6 but also states: "The number of tie down points may vary depending on your vehicle model"
I ordered 2 tie down hooks and 4 bolts online from a Ford parts place in New Jersey for around $35 shipped.
Thanks! I'll try that. I was going to use a piece of hose like a stethoscope to try to pin down where the noise is coming from, but it is definitely coming from somewhere around the window.