DWM Luger

I have a chance to purchase a 1900 Swiss, 2nd model safety, 95% blue 90% straw, area under safety polished bright as are the interior surfaces, grips 97% sn 26xx. How can you tell if it is a Swiss reblue? I know some were originally blued in Switzerland after being delivered from DWM in the white and that most were at sometime refinished there to a near perfect finish. Also, How doe you tell if this particular pistol is in the military contract range or the commercial Swiss range?? What are approx. values as I havn't seen to many 1900 Swiss for sale recently. Any and info is appreciated! JJV