Hard to say. What is in the contract? I don't know (I assume it is public but I don't know how to look this up). Different countries may have different contracts.
I wouldn't be surprised if the contract was only that X doses would be provided to the US market (as opposed to shipping to the market in Mexico...). In this case the government is only buying a spot in the shipping queue, and not any doses.
It could be that the doses were bought by the government only for the government (military and politicians), and the rest of us are on our own. (this seems unlikely - doctors should be first in line, but an obvious extension is the doses are for doctors/nurses and the leftover for the above)
It could be the government is buying all doses for their country and will distribute them for no extra charge. This is probably what Europe has done/will do - because they tend to have government health care for anything considered essential.
I wouldn't be surprised if all 3 of the above were in use by different countries. There is disagreement as to which is best on a political level.