I have a SP101 that I have owned for about 30 years. I had not paid a lot of attention to the details until I decided I wanted to get another caliber. I have the original box and most of the paperwork. What I am confused about is the "Catalog No". The sticker on the original box lists "KSP-183". I am including a picture of the gun and box. I don't see that catalog number in any of the reference material I have checked. What am I missing?