For some towers where people get to choose a path prior to requiring purchase of points (archer, poison), this does work.
However, towers where you need to purchase points to unlock an entire path (necromancer, artillery, zeus, sorcerer) this does not work. Like people who have the upgrade path cannot even select other paths because they have not "selected a path", even though they cannot.
I don't know if this is true, but sometimes, a singular path (ice, quake, mage) is unavaliable due to someone not unlocking it prior, even when someone else has the full path.