You want the rake, unless the whole suspension is very stiff.
The rake is there because all of the added cargo load goes on the rear springs. When loaded, the truck levels out. If you reduce the rake with a smaller, lighter spring you may have reverse rake when loaded with gear.

You should look at your expected loads and the spring capacity of the rear coil spring you're considering. Do you have heavy mods such as a rear steel aftermarket bumper, a tire carrier or fuel cans loaded on the back? You need enough spring capacity to compensate for fixed mods and added cargo loads, without significantly dropping the rear wen loaded.