GUIStyle.padding  

// Prints the left, right, top and down values of the GUIStyle padding

private var rctOff : RectOffset;
function OnGUI() {
if(GUI.skin.customStyles.Length > 0) {
rctOff = GUI.skin.customStyles[0].padding;
Debug.Log("Left: " + rctOff.left + " Right: " + rctOff.right);
Debug.Log("Top: " + rctOff.top + " Bottom: " + rctOff.bottom);
}
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
private RectOffset rctOff;
void OnGUI() {
if (GUI.skin.customStyles.Length > 0) {
rctOff = GUI.skin.customStyles[0].padding;
Debug.Log("Left: " + rctOff.left + " Right: " + rctOff.right);
Debug.Log("Top: " + rctOff.top + " Bottom: " + rctOff.bottom);
}
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

private rctOff as RectOffset

def OnGUI():
if GUI.skin.customStyles.Length > 0:
rctOff = GUI.skin.customStyles[0].padding
Debug.Log(((('Left: ' + rctOff.left) + ' Right: ') + rctOff.right))
Debug.Log(((('Top: ' + rctOff.top) + ' Bottom: ') + rctOff.bottom))