Would Larry Holmes had done better in a rematch with Mike Tyson with a few more matches under his belt?

   

About the same i would say.

Why did Mike Tyson not fight Larry Holmes again? - Quora

Lets say that they met again 18 months later, in the middle of -89.

Holmes has had 4–5 fights more, his ring rust is gone but he also is older, almost 40 years old and probably fighting at around 230 pounds.

Tyson is in decline after firing his original Team Tyson the previous year, but he is only 23.

In July -89 Tyson fought Carl “The truth” Williams who 4 years earlier gave Holmes a really tough fight, that Holmes won by a controversial decision.

Williams actually boxed quite like Holmes, so he is a relevant meausuring stick.

Both Holmes and Williams relied much on their excellent left jabs. But both also often held their guards way to low, resulting in an often flawed defense.

They brought out their left jab low and brought it back low, making them vulnerable to right hand counters.

Tyson stopped 29 years old Williams in 93 seconds.

The boxing genius Cus D'Amato (Who according to Tyson called Holmes a bum) trained Tyson from day 1 to beat specifically Holmes, and Tyson who was a student of boxing was given the blueprint on how to beat Holmes by D'Amato.

“Because when he throws a jab, he doesen't move his head. He stays stationary in one place. And if you're not afraid to throw the punch and by then you wont be. If you're not hesitant to throw it and not worried about getting hit, you can time the right hand right over it and you knock out Larry Holmes”.

-Teddy Atlas explains D'Amatos blueprint on how to beat Holmes.

Tyson executes it perfectly !

After their actual fight Tyson said

“I've known Larry Holmes style for years, i wasn't worried about him at all. I just saw the opening. Even when he was champion he was vulnerable to the right hand. He kept his left hand low and i threw my right”.

In -89 23 years old Tyson stops 39 years old, not rusty Holmes basically the same way as in their actual fight the previous year.

My humble opinion is that Tyson always had Holmes number, even peak vs peak.

Yes Holmes went the distance against Holyfield in -92, but Holyfield wasn't a pressure fighter.

And after Holyfield got cut in the 6th round from an elbow by Holmes, he took a much more careful approach because he didn't want to risk worsening the bleeding cut that bothered him for the 2nd half of the fight.