If the action was registered as a rifle initially, yes $200 SBR tax. If you start with a bare action that has never been anything you can build it as a pistol with no headaches. At least that's what BATF told my friend. I asked the same question.
If you buy a complete action it has to be sold from the manufactured as either a rifle or pistol action. SAKO doesn't make pistols.
Well, I guess my buddy's in deep kimchee then.