Another easy way to tell is going through the brochure for your year for the features. Here's the 06: http://www.meadowlandford.com/2006%20F150_brochure.pdf
You can see a variety of other years by correcting the 2006 in the link.

 

I bought my truck slightly used so I just emailed Ford through the Ford Owner's website and asked for them to send me all the factory specs. I few weeks later I got a nice letter (hand signed by someone in the "research unit") with my VIN breakdown and a list of all the included trim/options.

https://www.flmowner.com/servlet/Con...FContactUsPage

PS - if you sign up on that site then you can download pdfs of all the owner's manuals for your vehicle as well.

 

You're right about the FX4 in the console. I have the 60/40 seat and have no FX4 in the console only the PRND21