I belive its from the change over time . So most likely Interarms parts and S&W assembly. Might be worth something down road as a collector. But I don t know to much,just ask my teenage children or my wife. If it shoots good and you like it be happy If Smith had there hands on it and it works be very happy.
I agree it's a leftover Interarms, the last of the guns that look like a "real" Walther. I've also never seen a blue S&W so far, only stainless. I've got one of the last Interarms PPK in stainless but it's still marked with the Interarms logo and was made in late 1998.