They should but sometimes do not. If your son was not in the seat, they may not really want to but you never know. Read up on your warranty, some companies say the warranty is void if the seat was in an accident. The only thing is that if you "trashed" your seat, the insurance company will have no "salvage" to show for thier reimbursement. There are ways around that though. They can code an injury settlement check to get you the money so there are ways around it and they should reimburse you. If you still have your seat, the insurance company will want it. When a car seat has been in an accident, the insurance company (or the one I worked for did) will take the seat and cut all of the straps off so it is not used by someone else that randomly finds it in a dumpster or something.
Let me know if you have other questions and good luck!