SP89 and K grip question

Here's the deal. Does the K grip fit any other firearm you have? Probably not. So mere possession of it along with the gun it fits means it can only be assembled in one way, an illegal AOW and that constitutes constructive intent. The same as if you had it on the pistol. Get rid of it or at least get it off the property and have a friend keep it until you get rid of the gun. Then you can have the K grip and sell it someplace.

This is just like the AR-15 pistol build thing about having an pistol using a CAR length buffer tube and a stock that fits the CAR buffer. If you own a rifle length upper or other AR rifles, then owning the stock is OK since it can be fit to other rifles OR to the pistol when the rifle length upper is on there (TC ruling). But owning JUST an AR pistol AND a butt stock that fits it (without also owning other AR rifles or at least an AR rifle length upper) means that the only way the butt stock can be assembled on any of the weapons you have on hand is in the form of an illegal SBR. That is constructive intent and carries the same penalties as if you had the stock actually on the pistol.
This is documented on AR15.com in a letter I received dated November 2004 from the ATFE regarding pistol builds using AR-15 stripped lowers and CAR length buffer tubes. There is a little more in the explanation above than is listed in the letter but it was info clarified in the form of communications with the ATFE.