Simple Code

#define PLUGIN "VIP Menu"
#define VERSION "0.1"
#define AUTHOR "laymon91"

#include <amxmodx>
#include <reapi>
#include <hamsandwich>
#include <weapon_skin_system>

#pragma semicolon 1

enum SkinInfo { SkinIndex, SkinWeaponid };
enum Skins { SKIN_M4A1 };

new g_iWeaponSkins[Skins][SkinInfo];

public plugin_init()
{
	register_plugin(PLUGIN, VERSION, AUTHOR);
	register_clcmd("say /respawn", "Respawn");

	RegisterHookChain(RG_CBasePlayer_Spawn, "CBasePlayer_SpawnPost", 1);
}

public wss_loaded_skin(index, weaponid, name[])
{
	if(equal(name, "M4A1 Arena"))
	{
		g_iWeaponSkins[SKIN_M4A1][SkinIndex] = index;
		g_iWeaponSkins[SKIN_M4A1][SkinWeaponid] = weaponid;
	}
}

public Respawn(player)
{
	ExecuteHamB(Ham_CS_RoundRespawn, player);
}

public CBasePlayer_SpawnPost(const id)
{
	new user_has_prim = get_member(id, m_rgpPlayerItems, PRIMARY_WEAPON_SLOT);

	if(wss_get_weapon_skin_index(user_has_prim) != g_iWeaponSkins[SKIN_M4A1][SkinIndex])
	{
		rg_remove_items_by_slot(id, PRIMARY_WEAPON_SLOT);
		wss_set_user_skin(id, g_iWeaponSkins[SKIN_M4A1][SkinWeaponid], g_iWeaponSkins[SKIN_M4A1][SkinIndex]);
		rg_give_item(id, "weapon_m4a1", GT_APPEND);
		rg_set_user_bpammo(id, WEAPON_M4A1, 90);

		client_print_color(id, 0, "Weapon Index: %d", user_has_prim); // don't show index
	}
	else client_print_color(id, 0, "Weapon Index else: %d", user_has_prim); rg_set_user_bpammo(id, WEAPON_M4A1, 90); // index -1
}