Just drive it for a few days and see if the codes come back.
Should be fine
EDIT: Should give more detail.....
Disconnecting the batt doesn't always clear the codes, unless it was disconnected for 12+ hours. Some may say it doesn't take that long but my experience says it sometimes does. The codes could have been from messing with the car in the past. It take ~50 hot-cold cycles before the codes will disappear on their own. When you set the ECU back to normal all was reset.
Should be fine
EDIT: Should give more detail.....
Disconnecting the batt doesn't always clear the codes, unless it was disconnected for 12+ hours. Some may say it doesn't take that long but my experience says it sometimes does. The codes could have been from messing with the car in the past. It take ~50 hot-cold cycles before the codes will disappear on their own. When you set the ECU back to normal all was reset.