mel-
I have a little experience in dealing with your accident. I've worked as a bodyshop manager for a medium sized shop and as a claims investigator for a large insurance company. Keep in mind that I am looking at your claim from the standpoint of Kali law and it may/may not pertain to your state.
Firstly, the insurance company is obligated to repair your vehicle to pre-accident condition. If you have a vehicle older than five years, they do have the option to use wrecking yard parts. If you believe new parts are the only option, you are shooting for the moon and you will get nowhere on your claim. Best to do is rather than handle this matter yourself, drop off the truck at a bodyshop you know and have them deal with it. They are under no obligation to use the wrecking yard part and can reject it BASED on their professional background. You as a private party won't have the background to stand up in court if ever makes it to that point. More than likely, it will be forever stalled in depositions and discovery. I don't see you being out of line using a wrecking yard bumper and requiring the insurance co. to have it delivered to your place or even to one of the lizard's DRN(direct repair network) shops and have them install it after you have looked over the part. I know you'll fix the truck, unfortunately most people who handle their own claim, just pockets the money and never fix the part that was paid for. Btw....that is insurance fraud when people do that stuff.
My suggestion is find a happy medium between your new OEM and her wrecking yard bumper. Rather than take the check, leave the truck with her and have her shop put it on AFTER your approval of the part. Visually compare the condition such as nicks, scratches and gouges (if any) on the rub pad between your damaged one and the "newused" one. The same goes with the condition of the chrome and if it is bent or not. If you do reject it, be prepared to explain why. lastly, look only for the condition of your bumper before the accident or you will get stonewalled by the insurance company.
good luck!