This is an other long forgotten variation.
There are two (major) variations for all the southern Bells.
The Malaysian version and the Canadian Version.
There is always a paint variation between a Canadian and a Malaysian, but the paint variation is usually never noted. The main variation is where it was made.
The dark green door on the out building is the Canadian version and the blue door (teal) on the out building is the Canadian. The Canadian is the more rarer of the two with a production number of somewhere around 500.
My Malaysian # 4593 has the teal door.
I would not pay $50 bucks for a differant colored door, but I would pay an extra 50 for a Canadian made. Make sure it is a Canadian.