If you think you can train the same as MT just without face punches to prepare for a Kyokushin tournament you're mistaking. You'll be really confused when someone is going to walk you down and blast you with all kind of strikes and you won't be able to punch to the face or clinch.
If I were you I'd get as much sparring in as possible vs. real Kyokushin practitioners to get used to the distancing, the way they move and set up their strikes, their combos, etc. This is probably also a good way to condition your body because it's quite gruelling to the body.
I've seen a few Muay Thai guys trying to fight in Kyokushin tournament and they usually either get disqualified for fouls (punching the head by reflex especially when they get sworn by attacks, excessive clinching, grabbing the gi or the kicks, etc.), or they lose decision after the first round because they're too passive - there's a decision after every round so you could lose after the first round which means you have to go all in from the start, unlike in MT where you have 5 rounds to go through so you gotta pace yourself- or they get KO'd by flashing kicks they're not used to (spinning heel kicks, rolling thunder kicks, close range Brazilian kicks, etc.) or even finished by low kicks. Thinking of it I can't recall seeing any of them going very far in any tournament to be honest, they're usually just not accustomed enough to the rules and type of fighting.