I believe the only time you need to be concerned about a leg ring is if you're dealing with CITES birds like a grey, where they are regulated, AND if you want to bring him into another country. If you don't plan on migrating, you should be ok without a ring.
That being said, I do have our little guy microchipped, but I also have a ring on him.
Your ring options in the West are going to be closed leg rings (put on when they're babies) and open leg rings (put on when they're too big for closed leg rings to slip on them). Considering the age of the bird in question, you'll probably be looking at open leg rings.
Now open leg rings are a bit risky because it's a lot easier for them to get caught on things, like toys, cage bars, etc. Which means it puts your bird at risk of get caught, panicking, and hurting themselves.
In the East, we have leg chains (which are illegal in some Western countries). So I used a C-hook (without the hook park). It's a jointed ring, that we closed with a nylon nut and bolt.
The reason why we put a leg ring on, despite microchipping, is so that it's easier for someone to find us if he gets lost. Our leg ring has my phone number on it - not a random set of letters and numbers. So anybody can look at Cairo and, without touching him, know what number to call, rather than having a stranger try to capture him and risk him spooking off.