Almost every company has one or two weird questions.
If you go to an independent agent that represents 5 companies and is going to price you in all of them they are going to end up with a half dozen or so odd questions.
If I were looking for insurance and I had a large value of guns I would look at Liberty Mutual. The ISO forms have a LOW limit on firearms, but most companies make modifications and have tiers.
Any time you are going to insure any sort of valuable collection the agent will want info. During my short time as an agent I collected info on musical instrument collections, coin collections, antique collections, etc. It is a pain in the butt and if the things are scheduled it usually takes more time than the commission is worth, but if you don't want to do it then don't come back and complain when the insurance company is hassling you about your theft claim where all your undocumented under-insured guns were stolen.