That's the thing about SV cooking - the temperature is essentially the same throughout the meat. There is no gradient between the outside and inside, once you reach thermal equilibrium. There are charts for time versus temperature to make sure that the meat is safe to eat. So, yes, it is cooked at 124F, provided you do it long enough. One picture is worth a thousand words, as they say.
Here's the time/temp chart.
ChefSteps-SousVideReference - Time & Temp.pdf