Stainless steel interarms Walther PPK/s

[chief6309]

I have a Stainless Steel Walther PPK/s. The serial number is S002501.
1. On the left side as seen from the back of the gun on the slide is a; The Walther banner. under that is ; MADE IN USA behind that is; under license of
Carl Walther Waffenfabrik Ulm/Do.
under that is; ModellPPK/S Cal 9mm kurz/ 380ACP
On the right side
INTERARMS
under that is
Alexandria Virgina The interarms compass is missing.
I don't know when the gun as made, but I must have bought it in the mid or late 80's. The gun store were I bought the gun was not the seller, the seller whose name I do not remember was introduced to me as the or one of the factory reps for sales. He represented the gun as being the first stainless steel production model. He stated that the first stainless steel gun produced serial S002500 was a engraved model and ended up in a museum. the factory rep stated that this gun was the first of the regular production run.
I don't remember how much I paid for the gun, but it doesn't seem that it was much if any more than the usual retail of that time. I have fired it on many occasions, but not at all in about 15 to 20 years. I really am not interested in selling it, but I might be interested in concealed carry if I ever get off my butt and take the course.
My question is does anyone know where I can find the production serial number run, and or when the pistole was made, and or was this really the first pistol in the production run?