Airpods Serial Number Problem

5 days ago I bought my first Airpods Gen 2. And today for no reason I wanted to check the serial numbers on the right and left Airpods. When I checked it, I noticed that the serial number on the left airpods was different not only from the right one but also from the case. So my left airpods, right airpods and my case have different serial numbers. Since I use Airpods for the first time, I don't know if this is normal or not. It would be great if anyone that has Airpods check theirs too and help me. Thanks in advance.