If you research this, it all gets pretty baffling I must say. As far as I can determine (and my head is spinning), if you have Max Tow you already have the HD package UNLESS you get the super crew with the shorter bed, then you don't get HD package. So if you have the 8' bed, you probably have the Hd package and so you can tow 11.5K. but since you have the shorter bed, I'm in doubt here so hesitate to give you a green light. Some say yes some say no.
Another site told me that the 11,500 lb rating is actually stamped somehwhere on the rear bumper, so you might check that out as well.
really sorry to be a little vague, but Ford itself seems to be a little vague.
I also read somewhere that 7-lug wheels are a tip-off for the HD package.
Here's a site to download the 2009 Owner's Manual
and this should have towing info in it--maybe that'll clear it up.