OE Trans for 2wd or 4wd?

[69ROTROD]

Hey all...I have been plugging away on the '72 and finally found what is left of the factory option sheet that was in the glove box. It is pretty cool but raised a question.

My truck has 5 lug front axles and 6 lug rear. I figured somebody may have done a swap for a new brake setup at some point. The truck came with the M49 "turbo hydra matic" trans. Everything I have looked up said it was the 4wd trans option. Am I accurate in thinking that this truck started it's life as a 4wd and later became 2wd?

It was nice to see the LS9 and YE9 on the sheet!

Thanks for your help guys!