Uh, no, a DEALER cannot hold the guns in order fro a trust to be settled. That would be an illegal transfer. Actually the guns (assume NFA) could be held by the estate executor who most likely would be your wife anyway until a Form 5 could be executed without tansfer tax.
A trust is not at all required in order to assure transfer to a family member upon your death. Any legal heir can receive the guns upon approval of a Form 5 which is usually done pretty quickly, and all that's required is that your heir be named in your will.
Your state/local law may have other requirements. These are federal.