Yes. The previous generation 15" MacBook Pro has a 99.5Wh battery. The 2016 & 2017 15" touchbar MacBook Pro has a 76Wh battery. The 2018 model was upgraded to 83.6Wh. Depending on which version you have, you get either 15% or 25% less battery than the older model.

I got the figures from https://en.wikipedia.org/wiki/MacBook_Pro#Technical_specific... and https://en.wikipedia.org/wiki/MacBook_Pro#Technical_specific...