Christopher and Sherry’s home in Boston is filmed at the Warner Bros back lot on French Street – it’s not far from where they film the town meetings.
There are green balloons out the front, because “green is the new pink”, so green for a girl baby. Although Lorelai and Rory think this is strange, I’ve heard of people using green for gender reveal parties because they are “so over” pink and blue, or to make a statement about gender neutrality, or they simply don’t know the sex of their baby (so why have a reveal party to reveal you don’t know anything???). So this trend ended up becoming mainstream. Sherry was ahead of her time!
The green balloons signal “green for envy”, because Lorelai is very jealous of Sherry.
The Annotated Gilmore Girls 