Honestly, i have my doubts.
While filming the Passion, he was married, living a Catholic life as much as he could, being married to a protestant.
Since then he has gone through how many mistresses and had how many bastard children? (They are mistresses since he is legitimately married Catholic.)
I feel for him. The Hollywood culture is a nightmare. He needs to get out to save his soul.
What you observed is that Gibson doesn't "add-up" as a Catholic, does he?
Consider this perspective:
The media PR we were fed, is that he's a trad Catholic.
(Pssst... and by the way, trads are bad people... drunken adulterers who father bastards).
Another sign is the content of Gibson's film portfolio, which is off-the wall.
So, at best Gibson is a very down & out trad.
At worst... he's an imposter, working covertly for Hollywood jewery.