Changing GUI Texture with mousewheel?

I am working on my weapon HUD, and want to change the Texture with mousewheel. Here is my code.

using UnityEngine;
using System.Collections;

public class WeaponHUD : MonoBehaviour {
	public Texture Unarmed;
	public Texture Pistol;
	public Texture Shotgun;
	public Texture Carbine;
	public Texture AK;
	public Texture RPG;

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		if (Input.GetAxisRaw ("Mouse ScrollWheel") > 0) {
			if (guiTexture.texture = Unarmed) {
								guiTexture.texture = Pistol;
			}
		}
	}
}

Works fine for pistol, as I currently have that set only. My problem is, I can’t get the others to work as well. Please help.

The typical solution to this problem would be to put your weapons into an array. Then you can increment an index:

using UnityEngine;
using System.Collections;

public class WeaponHUD : MonoBehaviour {
	public Texture[] weapons;
	int iCurr = 0;
	
	void Update () {
		if (Input.GetAxisRaw ("Mouse ScrollWheel") > 0) {
			iCurr = (iCurr + 1) % weapons.Length;
			guiTexture.texture = weapons[iCurr];
		}
	}
}