I Fought The Colossus (Monsterbus p.147)

Eight ways to spot a Kirby story:

1. More than a twist: The plot does not ONLY rely on a twist at the end. It is satisfying even without the last panel.
2. Kirby did the layouts.
3. Description above the title.
   Kirby's stories were richer so needed the extra introduction: see Challengers, New Gods, Eternals, etc.
4. Every page is rewarding.
   There's something new and interesting on every page: it doesn't merely tease the ending.
5. Reality: The story is based on science, or history, or something else from the real world.
6. How would I defeat...?
   The story has you thinking how to beat a new threat. And the solution is something that would work in the real world. Kirby said in interviews that he got a kick out of thinking up some wild new threat and then thinking "how would I beat it?"
7. The dialog fits the art.
   The amount of dialog does not look squashed in awkwardly: it is roughly what the artist (Kirby) intended.
8. Originality.
   The story is either original, or has not been used for a couple of years and adds something interesting. But if it's just the fifth "alien invasion with a twist" this year, then it was probably suggested by someone else.

In short, intelligence.

This story for example is based on Kirby's Ultivac story from Challengers. But hat was a couple of years earlier for a different company, and here we focus more on human ignorance (merely a subplot in the much longer Ultivac story). And defeating a heavy machine by luring it over a cliff onto rocks is realistic. Assuming you were the designer so had an idea of what it would follow.

Not every Kirby story would include every one of these items of course, but based on my reading so far I think they would all have more than half of those features, whereas a Lee story, even when copied from a Kirby story, has less than half.