You seem to be a DC guru able to recall chapters like that.
Lol, when I was younger and the DCTP forum was active, I was fascinated by
legit DC scholars like Chekhov MacGuffin who seemed to know everything about Detective Conan, even more than Gosho himself! You don't know how many times they pulled out the most obscure interview Gosho did to back up their arguments, but I digress...
However in the Sunset Mansion flashback where Kid steals the clock tower he dueled and was almost cornered by Shinichi in a helicopter giving instruction to the police. That must mean Shinichi knew about Kid prior to Chapter 1 right? So turning into Conan and seeing Kid in 156 ought to be a "oh hey it's you".
Well one answer is that there's a parallel universe that Shinichi never interacted with this version of Kid unlike he did in the Kaitou Kid's manga and Detective Conan anime until Shinichi became Conan but that's answer is boring.
For the flashback itself, I think Shinichi knew absolutely the bare minimum of anything about Kid and that he is a chameleon thief that is planning a heist at the clocktower. Like you said, Shinichi didn't know nor had a chance to see Kid's physical description (which doesn't help that Kid's a chameleon) and Shinichi didn't even know Kid's alias! When Shinichi asked Megure about the name of the thief, Megure was too engrossed in the code Kid left behind to answer and Shinichi just left it like that. We just have to assume Shinichi never did any further research on Kid after stopping him until chapter 156.
https://mangadex.org/chapter/9e7fde0c-c09d-4015-96ae-ab80ed17790b/15
Even if he never seen him face to face, when Kid disappeared in a flashbang Conan was shocked even though in Sunset Mansion flashback one of Shinichi's instruction when Kid disappeared among the police was to check for one of them for disguise.
Hm, it's just a different feeling seeing a disappearing act up-close vs. knowing Kid will come disgusted. Maybe Conan was overthinking which he sometimes does on simpler problems.
Besides, it was Shinichi first camo in Katio's book. Gosho was doing everything to make Shinichi look cool at the expense of making certain characters look foolish. I think it's same with Kaito Kid and his first appearance in this manga.