The FIBA rules have defined how points are awarded for an own goal.
If a player accidentally scores a field goal in his team’s basket, the goal counts 2 points and shall be recorded as having been scored by the captain of the opposing team on the playing court.
NCAA Men's Basketball rules are a bit more detailed in this regard (emphasis mine).
Rule 5 Article 4
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 scorebook but shall be indicated with a footnote.
So it looks like an own goal is worth two points only, irrespective of the location from where the ball was released.
PS: NCAA uses the term 'opponent's basket' while FIBA uses the term 'his team's basket'. This is down to the definition of own and opponent's basket which...