In my company they give us a stripe less while we're still in training. And we use junior co-pilots as relief-pilots or cruise-pilots (second officer). They are not allowed to take of and land just yet. Are trained for it, in case of, but have to wait till they're promoted to co-pilot. they will be on trips longer than 8:30 hours.
So in our case: 1 stripe - second officer in training. 2 stripes - second officer, or first officer in training. 3 stripes - first officer, or captain in training. 4 stripes - captain.