Yes, my extended warranty (National Auto Care - Pinnacle coverage ) does cover shocks. Now the issue may be trying to get the Dealership to duplicate or recognize the issue.My truck is out if the 3/36 warranty. I have the extended Ford ESP but it specifically states that shocks are not covered. They are covered in the Ford maintenance plan, but I don't have one. I'd check the paperwork with your warranty or give them a call to see if they are covered, they may be included.
I looked into rebuilding mine as an option and there are a few websites that do it like Hammer or TSW. I'm sure they'd be able to tell you if they are rebuildable if you give them a call.
Not sure about that part number. I was given ML3Z-18125-BM in the quote from my dealership, not -BN.