A 2003 will have come with the plastic clamp. I've done a ton of these saws. It's much easier to pull the cylinder than to work in that tight space trying to avoid it. Just 4 bolts. Need to be sure that the impulse nipple on the boot properly fits into the hole in the cylinder. If the saw has much time on it, a new ring as it's going back together is a good idea too.
The % of those clamps that failed was pretty high, but there were plenty of them that didn't. Still see a lot of these saws coming into the shop. Quick check is to use your thumb and see if the clamp is loose or not. If it's tight I just leave it alone. If it's loose then I usually change it. Of course, attrition has taken it's toll over the years and most saws that had the clamp problem have failed by now. Any survivors with loose clamps tend to be the homeowner saws with limited hours on them.