No. It means that the one model has 2.4 trillion parameters while the other has only 27 billion. I don't know the details about their architecture or training, but presumably they used the same or similar training sets for both and a conceptually similar architecture, scaled down. I'd guess they also have some techniques to re-use some of the work done for the big model for the smaller versions (if anyone knows more about this I'd be interested). The architectures cannot be identical by definition because then the parameter count would be the same. Subsetting the data to such narrow fields as you describe could risk losing some edge, there are a lot of emergent capabilities in those models and I don't think that emergence is fully understood yet. There are subject-specific models, but for far broader subject areas than you suggested, like coding or math or prose.
I'm sure composability is possible in principle, I'm just sceptical that it'll be a good long-term solution, for my originally stated reason. It's basically just The Bitter Lesson again, we may gain some short-lived edge by putting more domain knowledge into the algorithm, but ultimately (these days often: surprisingly quickly) it'll be outgunned by something that just leverages raw computation better.