As maxcichon said, check your logbook. Specifically look at service B, and it'll say all the things you need to do at certain mileages (or years). If you bought the car before the mileage or age listed, then assume the other owner didn't do it.

About the indication, it depends on when the last owner did the services. The time the service is needed could be way off from what it normally is, if the last owner did the services early or really late.

If you're paranoid about the maintenace, and havn't done a service yet, I'd suggest maybe taking it in and having a service B done on it. Then you can flash the maintenance countdown to start over.