Not all Greek Revival architecture has monumental columns and an entablature. Other clues are:
Opennings above and on the side of the door.
The middle part of an entablature between the raking cornice and the architrave.
Engaged columns, often no more than a board, especially at the corners of a building.
The molding around a window or doorway that projects near the top of the opening.
A pattern in strips or bands of intersecting elements, either painted or in relief, that forms a border.
A stylized honeysuckle motif.