This is amazing and what I have to say is by no means meant to belittle "serial number 1" but rather to invite further discourse.
Could it be that three Triple Lock revolvers with serial number 1 exist, or at least existed at one time?
Let me explain further.
Serial number 1, with a 6 1/2" barrel in .44 Special, having shipped circa 1907, most likely with a blued finish.
Serial number 1, identical to that described above, in .455 Webley, produced for the British government circa 1914.
Serial number 1, this gun, produced possibly nowhere as early as 1907, but maybe so, marked as serial number 1 as it was the first cutaway produced.
Interesting that it has a 4" barrel because my observations, completely unofficial, is that true early production consists of solely 6 1/2" barreled guns, blued finish.
Which leads to the creation of another thread...