In a short scene at the office of Noah Bennet a woman, obviously an employee, walks by on the floor and greets him. This is Lisa - played by Karri Turner - who visited the Bennet family in the role of Claire Bennet's biological mother two episodes before.
Both Matt and Ted Sprague (the radioactive man) have an identical distinctive mark on their shoulder. Matt's is on the right one and Ted's is on the left one.