Sorry for the delay. I was eating dinner.
Here's the point: you would think that if the state where you were convicted restores your gun rights that the Federal government and any other state would be happy with that, but you'd be wrong.
The Federal government requires a expungement, set-aside or pardon before it will restore 2nd amendment rights to a former felony offender, even if the state would restore his rights another way. Idaho, too, has its own requirements for the restoration of gun rights with which you'd have to comply.
Idaho will automatically restore gun rights to most felons after the discharge of their Idaho sentence. But for people convicted of felonies in another state they require:
that the conviction must be "nullified by expungement, pardon, setting aside the conviction or other comparable procedure," or that your "civil right to bear arms either specifically or in combination with other civil rights
has been restored by any other provision of Idaho law. "
So, the WA set aside or a pardon (Washington doesn't expunge) should satisfy the Federal as well as Idaho's requirements.
Here's the law of Idaho as to the restoration of rights. If you don't want to hire a lawyer and go for the Washington set-aside or pardon, look at subsection (3)
You should be able to apply to the Idaho Commission of Pardons and Parole
for the restoration of your gun rights in Idaho, though that would not get you your Federal rights back.