Probably. Some much more so than others. Our ears and lips naturally bring most of them into tune (hopefully) since there is a decent range around the dead center of a note that still sounds full and warm. Others take a little more conscious effort, and perhaps a little hardware help with slide adjustments or alternate fingerings. Ideally we'd be able to adjust the hardware to be the perfect length for every note, so that we are always in the dead center of the pitch. But that isn't the case. Oh well. And whoever said that the pitch was dependent on the music and group had a good point. It's common to stretch or shrink an interval to better suit what our ears tell us, not what the tuner says.