From the Kel-Tec owner's manual:
This warranty is granted by Kel-Tec CNC Industries, Inc. , Cocoa, FLSince at this point you have no money invested, even if they charged to repair it, I think it would be worth a call to inquire about cost. If your friend that gave it to you is close by, you may ask him to make the call as the original owner but if they fix it, he may want to keep it.
This lifetime warranty is effective from the date of purchase and applies to the original owner of a Kel-Tec pistol.
Kel-Tec handguns are warranted to be free from defects in material and workmanship.
Any such defects of which Kel-Tec receives written notice by the original owner, will be remedied by Kel-Tec without charge within a reasonable time after such notification and delivery of the handgun as provided below.