[Ner0x96]

Код:

new wep[2];
GetPlayerWeaponData(playerid, i, wep[0], wep[1]); // wep[0] = weapon ID - wep[1] = ammo of the weapon
if(gCheckPlayerWeapon(playerid, putweaponidhere))
{
	if(wep[0] == IDWEAP && wep[1] == 0) RemovePlayerAttachedObject(playerid, 4);
	SetPlayerAttachedObject(playerid, 4, 349,1,-0.102073, -0.200483, 0.094914, 15.186383, 61.980533, 357.054473); // Here put the attach of the weapon that you want
}

Try with this