Frame/Model Number Decoding

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My 1971 3/4 ton frame is tweaked out at the front bumper and I need to have it straightened. I have the Truck Chassis Service Manual and it has the dimensions on it but for several models. None of these Model Numbers appear to match anything in the vin or the numbers stamped on the frame itself.

For example, the book has Model Numbers such as:

CA 107
CA 109
KA 107
PA 100

I can pretty much figure out what the dims are supposed to be but I am curious as to how the model numbers play into which frame I have.

Thanks for any response!