Government National Match Reworks รข?? These pistols were assembled by government armorers with all parts marked "NM" and had a parkerized finish. Most will have "S.A." markings for Springfield Armory. Colt: S/N (approx.) 20,000 to 83,856 = Jan. 1913 to Aug. 19, 1913. (This doesn't sound right, does it?) Perhaps you need to provide a littel more information, I just made a lot of assumptions: (1) It is a government model .45? It must be a "national match"? etc. Suggestion: You can do a
www.google.com search and there are all kinds of places where you can look this up, etc. Hope this helps.
Ron