In general, most graduate departments have "flat" offerings to their incoming graduate students—everybody gets essentially the same level of financial support. There may be some differences based on the students' abilities to secure their own funding (for instance, a "bonus" or "premium" if they bring in an external fellowship).
Now there are some cases where graduate students have special fellowships for outstanding graduate students, but these are often highly competitive and require an additional round of review before the awards are made. However, the one example I am aware of announced the decisions at the same time as the admissions decision itself. So, unless you've been told at the time of admission that something like this might be possible, I would assume that your offer is going to be essentially the same as all other graduate students coming in. The school likely just wants to move quickly to get a better chance at retaining students it thinks are especially qualified.