[Basssiiie]

Code:

public OnPlayerSpawn(playerid)
{
	new pSkin = GetPlayerSkin(playerid);
	switch (pSkin)
	{
		case 280..284: // Cop skins
		{
			GivePlayerWeapon(playerid, 22, 500);
		}
	}
	return 1;
}

That's one of the many ways to do this.