What is the value of a Colt 6 shot single action revolver 1891 Kansas Centennial Model 1961?

Assuming you mean the Colt Scout Kansas Centennial which is marked on the left side of the barrel 1861 KANSAS CENTENNIAL 1961. Provided you have the original wooden presentation box, sleeve, all paperwork and the gun is absolutely new and unfired with in 100% condition, it would sell for close to $600. If you are missing any of the above, and especially if the gun has been fired or has any finish wear, the value would be about half that. sales@countrygunsmith.net