flingled

What do I have? From my research this looks like the 43rd Scoremaster made. I have read somewhere that the first Scoremasters had the Seattle address and the serial prefix "M"...and started with 2000. I can't find that history again. Can someone direct me where that information might be? This gun seems to be unfired and is in new/pristine condition. It also has the original mag and comes with two original boxes of .451 ammo...along with an additional reproduction box. How much is this gun worth? Feel free to email me at cmvance2@gmail.com I hope these pictures come through. -Charles