According to the Extract from the Archives of Patek Philippe, the present watch, a reference 647, was made in 1937 and left the factory on 18 June 1938 with silvered dial, raised hour markers and case no. 504'954. The original case back has however been replaced to a later date against the actual, associated and non-signed example.
Reference 647 was launched in 1937, year of production of this watch, and remained in production during a very short period of time only. To date, only three examples in stainless steel and one in yellow gold are known to have survived.