General Question about Sam Bats

[groundcontrol]

I had a general question about the writing on the end of Sam Bats:



The top number is the length of the bat: 33 in.
The second number is the weight: 31 oz.
The third is the date it was made: 3-3-08
The fourth is the model : 73
Does anyone know what the last number is?

[camarokids]

it is a batch number .....