I am only guessing, but I think you are just about right.
The last time I visited Borås would have been circa 1974/1975. Then the park looked basically like this map but with a few exceptions, like:
There was an Asian Steppe then - the part of the zoo that is today the rhino/cheetah savanna - but on this map is the flamingo/antelope enclosure.
So yes, round about 1980 or perhaps a little later?
BTW
This park doesn´t change in a very fast pace, but it was pretty good from the beginning (started up in 1962). Now and then new enclosures are opened up, though. Like the 7000 sq meter (close to 2 acre) african dog enclosure or the rhino/cheetah savanna (also 7000 sq meters) mentioned above. Right now a three acre+ enclosure is being built for the brown bears. It will open this spring.
