What year is my John Deere 120 Mower

[Firefightergeo00]

I just removed a John Deere Mower 120 out of my grandfathers barn and I’m trying to determine how old it is. These are the numbers below the steering wheel. I assume all the numbers mean different things. Thanks George
SN 12314003267 M

 

[JoeM(GA)]

all the parts book states is -
120 HYDROSTATIC TRACTOR
12 HP K301AS BALANCED KOHLER ENGINE
1970 MODEL (SERIAL NO. -007500)
1971 MODEL (SERIAL NO. 007501- )

 

[tom3]

Sometimes the engine ID code numbers will pin it down pretty close. Not sure where those numbers are on that older model.