I think there’s some truth in it, maybe the outline and topics were accurate but the scene description details were made up.
2 examples that come to mind quickly-
1st- Mobsters and maybe Henry when he was with Jimmy or Paulie would go to the Copa, get premier seating, and even enter through the kitchen- but Henry never got this treatment on his own, or on a date with Karen, that is all false, but if he went with Jimmy and Paulie he might have benefited from their power.

2nd- Luftansa robbery, I doubt he knew as much and was involved as much as the movie showed, I bet he barely knew anything about it, I bet he didn’t even know it was going to happen.