Ex claims guy here. Your equipment and vinyl should be covered (up to your policy limits) under a "normal" HO policy (SF, Allstate, Geico,etc). In case of a covered loss Replacement cost comments are correct but you will need to "help" the adjuster by providing receipts (if any) pics of equipment, LP's etc. Also where to find replacement costs for the more esoteric items (Used vinyl sites, Audiogon, etc.) Audio and LP claims are not that unusual so most experienced adjusters will have some experience with such claims.
If you do not have a normal HO policy from a major insurer I would definitely contact your agent and go over your policy and any limitations, exclusions.
If you do not have a normal HO policy from a major insurer I would definitely contact your agent and go over your policy and any limitations, exclusions.