It is unfortunate that these appraisers do not know everything, but what is most unfortunate is that they tend to lead people to believe that they do. But for the sake of the audience, travelling appraisers will often grasp at straws, giving an educated guess of what the item might be and an often uneducated guess about its age and value. This can be very disappointing to the owner of these items, not initially of course, but after several years, when they have paid several hundred dollars for insurance and a safe deposit box and are ready to sell the item and retire on the proceeds. Never use a general price guide that gives only a general description of the item. The value is, many times, based upon specific details.
Original condition is always very important to the value.
If you are aware of repairs that have been made to an item, point them out to the appraiser. Always remember that when a person pays forty thousand dollars for a toy truck, it does not necessarily mean that the toy truck was worth forty thousand dollars. It may mean that his forty thousand dollars was only worth a toy truck. The best assessment of value can be gained by an established track record of an item. Ask an appraiser for documentation of the assessment.