I never got a rider on my insurance policy because they wanted all of the info for the firearms. Not comfortable getting a list like that out there.
I have read nothing but good reviews for Collectibles Insurance Services (CIS) | Collect Insure and they dont require a list, just an FYI if you have been thinking about insurance but the list thing is holding you back. Prices arent bad either, think they start around $200 or so for $25-30k worth of coverage