Is it a Heritage (old body) or new?
My truck is probably 95% junkyard, but I did it over MANY years. I swapped the whole body when I rolled it.

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I've also built a few other trucks.

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I'd say the most important factors are a) having enough money to do it right & b) knowing what you're getting into. If you know you can find good replacement parts at good prices, and you have the time/space/tools/patience/budget to work thru whatever you find, then go for it. If the junker's title hasn't been tagged as salvage, then you might even come out ahead on the deal.
But you should know that there are a LOT of electronics in an 04; some that store wreck info, and some that won't work at all after a wreck, so they MUST be replaced & then reprogrammed by a dealer.