I not sure about the serial#'s starting with CH for China or T for commonwealth? My serial starts with a K. The two models that the John Ingless company of Toranto made were British and Canadian forces used fixed site version, while the tangent-sighted version was preferred by the Chinese.
The French wanting a better pistol after WWI approached Fabrique Nationale (FN) in Belgium for such a weapon. FN experimented with the double-column magazine and turned further design to John Browning. He came up with two designs. All of the rights to Brownings designs in North America were owned by Colt. Browning offered them to Colt, but they were not intrested. FN, however , was very interested. The 1922 FN Browning was born. Browning soon after finishing the initial development work, making the Hi-Power the last pistol he worked on. The first French trails required modifications that Dieudonne Saive of FN took over and the development of the model 1923. Since Colt's patent on the 1911 design ran out in 1928, Saive used some of it features in the model 1929 and soon the 1935. Defence orders before WWII went to China, Peru, Estonia, Lithuania, Sweden, Finland and France. In 1940, the Nazis invaided Belguim and managment of FN passed to DWM. Saive and other FN engineers and executives fled to London to avoid being force to produce arms for the Nazis. The British government allowed Saive (with blueprints) to go to Canada to assist Ingless with the start up production. FN had produced frames machining a piece of drop forged steel, while the Ingless factory was set up to flame-cut mutipule frames from rolled steel using acetylene pantograph. FN engineers found this method hard to accept, but it proved quite effective and speeded production substantially. Ingless produced (Once in full production) pistols at a steady rate from February, 1944 through September, 1945. 151,816 Ingless Hi-Powers were made. About 50,000 were made with tangent sights.
