I heard it from a historian in the City Chambers but hard to prove I think. There was a good chat about it here - https://www.reddit.com/r/glasgow/comments/5xdvc7/how_did_glasgow_get_such_a_clean_street_grid/.
I guess we were one of the first cities to do it along with the New Town in Edinburgh.
There is also a small Statue of Liberty at the top of the city chambers building overlooking George Square.