Dash harness differences

[Secondgensneedlove]

Hello all im inquiring to figure out the differences in dash harness's. I have a p56045364ai in my truck. Its a larmine quad cab 2002 24v 6 speed. The brake controller burnt up internally and shorted a whole mess of wires apparently according to the previous owner. So i pulled the whole dash apart to replace this thing. I have a harness i thought would work but it doesnt. I can however rob it of the circuts i need such as the brake circut that runs up to the heater control and wherever else. Sounds like a great time doesnt it. So that being said i did some searching and found a harness that appears to be identical. The part numer on it is p56045364AG the last letter is different everything else is the same. Similar tags just the last letter of his is a G and mine is an I. He says that he believes the last letter is how you tell what plant the truck was assembled in? Is this true? Can i use that harness instead of doing something i already loathe. 

[Great work!]

I can't  help with the part numbers but I changed a cab before. Put a 2wd quad auto gas 1500 on a diesel 4wd auto. Only one year difference similar options different radios. I had to change every harness over. Even above the headliner. I got it all done and the doors wouldn't plug in. Had to change the door harness too. Buy a set of those plastic body and trim removal tools to pull out the wiring with out marking the paint and plastic. They work great especially  the crow foot one.