So, it would not be a good idea to say they were stolen "a week from next Tuesday" ???
I guess my concern is that once reported as stolen, it will always be stolen. Keeping it next to your bed will essentially carry the same legal risk as keeping an unregistered machinegun next to your bed. You have no other choice but to bury it in a cache.
Should your days turn to twilight and you never needed to use your cache, you'll want to let a son or grandson know where it/they are. Unfortunately, as "stolen" weapons, they'll be able to do nothing with them other than keep them cached or run the risk of being caught in possession of stolen property.
By selling/trading/giving them away, you can always come back later and claim you happened to run across the guy you sold it to and bought it back.