Wiring help gmc vs chevy

[Missyblue]

Hey I need help. I have a 57 gmc and the precious owner bought a chevy wiring kit. The colors seem different so hoping someone can answer a couple questions
1. Will a Chevy harness work with my gmc gauges/lights/etc?
2. I was going to order a wiring chart should I then now order a Chevy chart for color coding?
3. Am I crazy and shoukd scrap it and do something else. They are just so expensive and this is a good set just Chevy
4. Any other thoughts to consider I'm forgetting

Thanks