If its a long string of numbers its probably the Serial Number of the rifle. This is an identifying number, unique to that rifle and that rifle only. When the rifle was issued to a soldier the Serial Number was written down in the records, and he was responsible for returning the weapon when he left the service.
Individual parts might have a number stamped on them, having to do with the production of the rifle.
your M1 garand was made in 1954
Your M1 garand was made in 1943.
Your M1 garand was made in 1944.
Your M1 garand was made in 1942.
Your M1 garand was made in 1945.
your M1 garand was made in 1945
An M1 Garand with that serial number would have been manufactured in October of 1941. My reference says that Garand was built during May 1945.
your garand was produced in 1945. the M1 garand was to become a weapon in the US arsenal starting in 1936.
The Springfield M1 Garand with the serial number 626541 was manufactured in 1944. The M1 Garand was produced during World War II, and this specific serial number falls within the range of rifles made in that year.
your garand rifle was made in 1945
your serial number is too high for garand military rifles
1945