Probably an inspector/assembly mark.
smith and Wesson 38 c t g e
S&W has not used a G prefix serial number.
Laurence G. Wesson has written: 'Physiology of the human kidney'
G. Smith has written: 'Changing times'
Nicholas G. Smith died in 1945.
Nicholas G. Smith was born in 1881.
M. G. Smith was born in 1921.
M. G. Smith died in 1993.
Jan G. Smith died in 1966.
Jan G. Smith was born in 1895.
Marcus G. Smith was born in 1973.
G. Carlos Smith was born in 1910.