Is it a fake EarPods or Apple changed it's design?

Recently I bought a good old EarPods with a 3.5mm jack. The main reason was its decent sound quality, and of course, a 3.5mm jack.

I was surprised, but the sound of the new EarPods was significantly worse than the old one I got with my iPhone. All things looking similar until I teardown it. I noted different speaker.

Also, I wrote to the seller, but they refused accusations that it was fake and insisted that it is 100% genuine Apple production. Very sad, but I can't check the serial number of any EarPods on https://checkcoverage.apple.com/.

So, does Apple changed the design of EarPods, which entailed in sound quality decline or I just bought a fake?