I think we need someone from Buck to answer this specific question. I don't see it specifically mentioned in the warranty. My opinion is they would work on the knife, but it sounds like it is their discretion whether they will charge you or not for the work.
The BUCK Forever Warranty
We warranty each and every Buck knife to be free of defects in material and workmanship for the life of the knife, and we will repair or replace with a new Buck knife, at our option, any Buck knife that is defective. Buck Knives does not warrant its products against normal wear, misuse, or product modifications. Buck Knives are not intended to be used as hammers, chisels, pry bars, or screwdrivers.
If your knife was damaged due to misuse, our repair department can analyze the damage and repair it for a reasonable fee. If the knife is unable to be repaired, we will extend a one- time courtesy offer, allowing you the option to purchase a new knife for 50% off of our MSRP price listed on the website, excluding any custom knives or web specials.