Yes mice do smell when they die of mouse poison.
The mouse poison works by preventing blood clots in the mouse and then causes internal bleeding eventually which can take a few days to happen after the mouse eats the mouse poison.
Then the mouse goes back to where it was usually hiding again and then dies within a few days to a week at most.
So you might see the mouse again for a few days after they eat the poison until the poison makes them sick enough to where they lay down and die.
As the mouse lays there and decomposes they will start to smell and after a week or two the mouse dead smell should go away.
So if you notice the mouse smell which is horrible when the mouse is dead it will go away eventually so if you cannot get to the dead mouse to remove them that's okay as the smell will eventually go away.