Currently no but getting the tile or object under cursor from mouse / press position is doable. Are you looking more to select the tile or the scene objects directly?
Node2Ds can implement mouse_entered() and mouse_exited() signals as a way to trigger things like changing color to show hover overs (or communicate with a UI to show info about the hovered node).
I could see how a selection mode would be helpful for the GridBuilder plugin itself though to show hover overs. Things like RPG statistics would need to be extended by game specific code though since there's no way to know anything but basic node information inside the plugin (Could just be as simple as a custom display UI during selection or hover)
Let me know what you think - if it should be more like selecting the tile and getting a list of objects on it or just showing info of the first object under the mouse cursor. I will add something like this to the list of requested features.