I hate to tell you this, but I think you have regulator for the heritage F150 (I realize that the distributor's website says it is for an '04 Lariat, but the new body style does not employ scissor-type regulators; their catalogue appears to be wrong). You need the new body style:
http://www.trademotion.com/partlocator/ ... atalogid=2
Return your regulator for a refund, complain about the inaccuracy of the website, and don't do anymore business with those folks. They obviously aren't on top of their game.
For what it's worth, replacing the window regulator is a pain in the a$$. When my regulator failed out of warranty, a local body shop ordered a new Ford OEM part (not a third-party manufacturer part) *and* installed it for under $200 within two days. My recommendation is to cut your losses and have it done at a body shop.