Question: A friend of mine gave me a Spyderco Police Model. Great knife, full serrations. Its flat ground, marked ATS-55. G-10 (?) scales. Why is this one flat ground all the way? All the current pictures I see, the blade has alot more grind lines to it. Is this Very new? Very old? Rare? I have several other Spydercos I could carry if this one has collector interest. Appreciate the help.