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'
Marcus G. Smith was born in 1973.
G. O. Smith was born in 1872.
G. O. Smith died in 1943.
Jan G. Smith died in 1966.
Jan G. Smith was born in 1895.
G. Carlos Smith was born in 1910.
Nicholas G. Smith died in 1945.
Nicholas G. Smith was born in 1881.
M. G. Smith was born in 1921.