If I was going to cache some firearms, I would not cache all. First off, I would sort by which ones have a paper trail. Those would be left at home for the JBT's to find. After all, they already know I have those ones . . .
Those with absolutely no paper trail (no 4473, no sales receipt, no gunsmith records, etc. ) would get cached with ammo and cleaning kits.
That way, if they come they will collect what they think I own. They will think they have it all. Later I can always acquire another collection by using what was stored away.
You can always keep a few to turn in in good faith and for the rest, say you sold/traded/gave them away. Copy of the classified ad you took out (you told all callers they were already sold) a handwritten receipt with drivers license # (how were you to know it was fake?) may be just enough to let you live. Probably not a good idea to report anything stolen though. If you ever give it to your grandson and he gets stopped for a traffic ticket, you don't want him to be in possession of a "stolen gun".