Serial Numbers:
Location: In front of gear shift
 
1939 B INA
1940 B INA
1941 B INA
1946 IB 1001 to 1002
1947 IB 1003 to 1009
1948 IB 1010 to 1281
1949 IB 1282 to 1555
1950 IB 1556 to 1878
1951 IB 1879 to 2218
1952 IB 2219 to 2569
1953 IB 2570 to 2847
1954 IB 2848 to 3072 INA-Speculation based on known production quantity
1955 IB 3073 to 3307 INA-Speculation based on known production quantity
1956 IB 3308 to 3407 INA-Speculation based on known production quantity
1957 IB 3408 to 3482 INA-Speculation based on known production quantity
1958 IB 3483 to 3592 INA-Speculation based on known production quantity
Comments:
 
The first 260 IB tractors built in 1939 - 1941 had Model B serial numbers and had 116ci engines.
Production in 1946 started with Serial No. IB1001 and had 125ci engines
 

B & IB Production
  B IB
1937 96 --
1938 11,699 --
1939 21,594 113
1940 16,119 70
1941 6,961 75
1942 4,619 --
1943 1,001 --
1944 4,678 --
1945 2,024 --
1946 1,107 2
1947 5,305 7
1948 7,608 272
1949 6,868 274
1950 7,186 323
1951 2,754 340
1952 1,906 351
1953 1,158 278
1954 314 225
1955 969 235
1956 380 100
1957 175 75
1958 -- 110
Total 104,521 2,850