This version of the Fort underwent several changes over the years.
Two different types of connectors for the wall sections were tried. First small tabs and then a fragile hook system.
The Fort was eventually down-sized in 1972 by leaving out 4 of the wall sections. this made it a narrow 5 x 2 shape.
The buildings were replaced with two small pre-assembled ones from the 2nd series, the Jail and Livery stable.
Artwork was used on the box instead of a photograph.
Later, around 1974, there was a further change in the method of attaching the walls.
This time, a bar and pin system was used.