As mentioned in the previous post on vray linear workflow settings, here is a quick script that will automatically create a .454 gamma correct node to correct your swatches.
Just paste this code into the script editor, and create a shelf button or assign it to a hotkey-
shadingNode -asUtility gammaCorrect; string $gNode[] = `ls -sl`; setAttr ($gNode[0] + ".gammaX") 0.455; setAttr ($gNode[0] + ".gammaY") 0.455; setAttr ($gNode[0] + ".gammaZ") 0.455;
Note- Make sure to have the hypershade or node editor open when running this code, as it will automatically be created in the work area