According to the late John C. Loring in his soft-cover book titled "The Dunhill Briar Pipe - The Patent Years and After": "From the 1920's through the 1960's a "C" was used in the shape stamping preceding the shape number to signify a churchwarden. Pipes of that period with churchwarden stems but no "C" in the shape nomenclature can be suspected of having a churchwarden bit later fitted to a pipe not initially intended to be a churchwarden."