Missing Cutscenes and Main Missions (Despite Finishing Game)?

[Fallout3]

So I've just finished the game today, but after looking up some videos on YouTube, I came across one for the mission Fame or Shame and it has an intro scene where Michael discovers a block of weed/grass or whatever and begins arguing with Amanda, before Jimmy enters the kitchen and Michael says "There you are you little sh**". But when I played it, it began right at the part where Jimmy enters the kitchen. Is this a possible glitch or is this meant to happen, depending on your actions and what you did with Amanda etc?

 

 

Also, after receiving a phone call from Dave Norton to Michael telling him to meet at Kortz centre, I decided to save and quit the game. After starting it up again, I had somehow skipped that mission and went onto the next one. I only realized this after Steve mentioned something about Kortz Centre near the final missions of the game and after looking it up, it turns out there was a mission there called 'The Wrap Up', though I had never seen it before. Did this mission possibly glitch on me? I have 66/69 missions completed despite finishing the game. Could one of the 3 missing ones have been this?

Edited October 2, 2013 by Fallout3