I thought that was the rule and maybe it was back then. However, while looking at the rules for this season (for another reason) I noticed this:
Art. 4. A successful try from beyond the three-point line shall count three points
for the team when the ball is thrown or directed into its basket.
a. When a player scores a field goal in the opponent’s basket, it shall count
two points for the opponent regardless of the location on the playing court
from where it was released. Such a field goal shall not be credited to a
player in the score book but shall be indicated with a footnote.
So a couple surprises there for me.
1) Any basket made in the opponent's basket only counts as 2 and
2) The score is indicated by a footnote and not credited to any player apparently.