Mike DePaz has found us an older souvenir sheet from Greece that was issued on 20 May 2015. It shows the breakwater lights on the harbor entrance to. Piraeus.
Pireaus Molos Themistokleus L/H, Piraeus Molos Vaseleus Georgios L/H | 20 May 2015 | N4178, N4180
Thanks, Mike!
See more lighthouse stamps from Greece here.