I obtained a Series 70 Colt Gold Cup National Match recently. The pistol has a number of features which appear to be similar to those found on pistols 'smithed by Mr. Swensen. These include a squared trigger-guard,safeties stamped as Swensen's,checkering etc. How would one go about determining whether this firearm was,in fact,worked on by Mr.Swensen? Any advice is appreciated. Thanks in advance.