If you have absolutely no reason to have your place searched an have a hiding spot for the guns that can never be found (IE: removable concrete with temp sealant to stash them behind) I say go for it.
If you do not want any type of risk, get em' registered. You can always take em apart when storing them. If the internals are remove from the shell they don't have to be registered.
I have the internals and te case for an AK47, though I have never put them together because it's a felony in Jersey to have this bitch. Bought both the internals and te case online as well, so I am definitely being watched. Keep em separate, yer good to go.