according to the Cameramuseum site the 1.8/50 "chrome" or "Ver.1" was sold from starting November 1951: http://global.canon/en/c-museum/product/s18.html
according to the more detailed information in Peter Kitchingman's book on Canon rangefinder lenses your's is a "Type 4", these have serial numbers 88596 to 170760 and were produced between 4/1953 and 3/1956. That would make 1955 the most probable year of production of your lens
The camera was an EOS DSLR and I was using just a simple M39 to EOS adapter for this image. I was maybe 8 or 10 inches away from the acorns when I took the shot.