replacement wiring harness

[68GRNK20]

The wiring for my 68 K20 came to me in a box and is not in the best of shape, I'm looking into a replacement one because after all it is almost 50 years old.
there is a different wiring harness for the 67-68 and the 69-72 I read that the difference is the steering column connector, is that the only difference? The 69- is always about $50 cheaper

another question brothers trucks has them on sale now, the picture they use looks the same as American autowire i'm guessing they sell aam