Is it just me, or do the more recently manufactured devices seem better?

Is it just me, or does it seem that the more recently manufactured 6P's are better in build quality, especially where the speakers are concerned, with sound through a headset? For example, my latest Gold 6P has a build date of January 30, 2016, whereas my original Aluminum 6P had a build date of October 31, 2015. The speakers on my Gold 6P seem to have a fuller sound. It's interesting.