different size clip rings?

i purchased 2 wakuku on a roll series from 2 different aliexpress sellers, i am very vigilant on making sure the stores are genuine, i make sure to find reviews with photos and good star reviews. so i ordered 2 different ones from 2 different sellers, they both look very genuine and great quality, but the clip rings on both are different sizes. not by a great amount but definitely noticeable. is this just a manufacturing change? i have no worries about them being fake, but just wanted to know if anyone else had experienced this.