They seem to just be using different words for the same thing.Don’t forget the refined ergonomic differences!
Like talking about the "refined 3 slot rail with extra indexing"... we can see from the side by side the rail is exactly the same. Other than the slide serration they pretty much look like the exact same gun. I wouldn't be surprised if you could swap out the slides on them without any issues at all. And the feature list on their site says the exact same thing for both triggers. When the Mod.3 came out the exact same words were used "Deeper, More aggressive" to describe the serration over the Mod.2.
I really do think they're just losing the profit margin over tariffs, and using the popularity (which is mostly due to the $325 MSRP to begin with) to re-release the same gun at a higher price.