If you want protection get an appraisal done and insure with whomever against the appraisal. Make sure the appraisal is recognized by the insurance company. With the appraisal you will have value documentation by an independent party. When the time comes that you may have to make a claim there is little wiggle room as to stated value. What ever you want covered has to be in that appraisal. I.E. winch, wheels and tires, lockers what ever wasn't on a factory built Bronco.
The insurance claims adjuster will try to get you to sign off on a lesser amount that’s his job to save the company money. After you turn down his amount shove your paperwork in his face and be prepared to get a lawyer involved to protect your interest.
Understand that your 35 year old Bronco has no value in its stock form to your insurance company. It’s just a worn out piece of machinery and its value is such. The courts uphold Nada, Kelly’s and Edmonds as values its up to you to prove your value above those limits and have the proper coverage against your claim. Your agent is as good as your recruiting officer, parole officer, or news paper boy. They don’t write the checks or enforce the rules of the court. So be prepared to fight or accept what Kelly blue book values are.