The FIDE Handbook indicates: (https://handbook.fide.com/chapter/C0401) "Should the number of players to be paired be odd, one player is unpaired. This player receives a pairing-allocated bye: no opponent, no colour and as many points as are rewarded for a win, unless the rules of the tournament state otherwise."
This allows the organizer to decide whether to award a point or a half-point for a bye.
There are some exceptions. For example, when the organizer is in charge of a FIDE event like the World Chess Championship Under-20. In that case, the organizer does not have the power to change the rules that were established by the FIDE Congress.
Something interesting is that, in the United States, an organizer of an USCF tournament can give a bye for players who do not want to play or cannot play. It is my understanding that in FIDE events that option does not exist.
As far as I know, when a FIDE rule is changed there is no record of the previous version, only of the new version. For that reason, it is difficult to find a document of 1989. However, I was born in 1966, and I started to play monthly tournaments in 1977 for around 20 years. I clearly remember that at that time in a swiss tournament, under FIDE rules, half-point was the standard for a bye. In spite of that, my personal experience proves nothing. That would be only anecdotal evidence. According to Wikipedia, anecdotal evidence is evidence based only on personal observation, collected in a casual or non-systematic manner.