Are we talking interstate? Intrastate-No you cannot ship him the gun if he does not have a FFL but in the same state you may be able to.
If the guy/stockmaker is in the same state as you are and,depending on the state laws,is not a felon,drug addict,liberal (ok I added that)over 21....,you may well be able to allow him to work on your gun stock with the reciever attached.Same as if you sold it.
My concern would be why he does not have a FFL if he is in the stockrepair business,is there legal reason?

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