Floortrader
What evidence do you have for the second stamp being 'fake'?

According to the Hellas 2005 catalogue, they are both bona-fide issues. The stamp you show on the left is C60, issued 12/6/24, cat value 3.5 euros mint in 2005. The one on the right is C61, issued 1926, cat value 1 euro mint. The 1924 is perf 13.5 by 12.5, whereas the 1926 is perf 11.5, as yours appear to be, and the re-drawn faces are obvious in the catalogue.
DavidR