Postecoglou memorably claimed recently that he was more bothered about what he was having for dinner than the new managerial appointment across the city, but he has done his research on Beale's methods ahead of the New Year derby.
The former Ibrox coach has secured four consecutive wins since his return to take charge and Postecoglou has noted some differences from the approach of Giovanni van Bronckhorst.
On his preparation for the game, the Celtic boss said: "It does change because, as I have always said, we treat every opponent the same way - we look at what they are doing currently rather than historical stuff.
"They have had a change of manager, which has meant Michael has come in and changed the shape slightly, he is trying different personnel. All those types of things are factored into it.
"We try and prepare our players for every possible outcome, but sometimes during games things change or are different, depending on how the game is going.
"For us, at the moment, one of our strengths is our ability to adapt mid-game - whether that's the way we play or by making substitutions where players come on who have different qualities.
"It's a bit of both but our preparations are always the same, regardless of the opponent, it's about what we think they are likely to bring against us in the current circumstances."
Celtic won 4-0 in the previous meeting between the teams but Postecoglou does not need his previous experience of the fixture to tell him that Monday's game is likely to be a tighter affair.
"You kind of know going into it that it's a massive fixture and you understand the significance behind every outcome," he said.
"But ultimately we have played in all of these fixtures with the same kind of mindset. We have got to perform to our levels, play our football, try and dominate the game in the areas we want to dominate.
"When we have done that, we have been very effective both at Celtic Park and obviously at Ibrox last year in the second game.
"But for the most part traditionally these games tend to be tight. There have been a couple that haven't been, in our favour, but you don't go into these games thinking they are going to be open affairs.
"It's going to be tight, both teams are going to be at it, and it's going to be exciting."
Celtic can go 12 points clear but Postecoglou stressed that the gap was "really, really irrelevant" at this stage of the season.
He added: "For us, nothing changes. We have got to be at it on Monday, the same way we have been for every game this year and we will continue to be at it after this game, irrespective of the outcome.
"How that affects other clubs is of no consequence to us.
"We have been really good at focusing on what's at hand. What's at hand at the moment is a cracking game on Monday against a strong opponent in a fixture that's global, that everyone watches. That's where our focus lies."