I hope this is the appropriate thread to post my question.
My late father was a navy officer and a lecturer in Maritime Acadamy. He had solid contacts when it comes to obtaining maritime philatelic items. The items below are from his collection, passed onto me.
I have heard about many fake GBLA stamps, or souvenir stamps. I have in my possession 4 stamps below - all mint, the last one has gum. In your opinion, are they the real GBLA stamps? Could not find them anywhere (tried various search methods).
And I have this envelope, which has the stamps with the names of the GBLA ships and also a "Djabiporst" postal stamp not found by me anywhere (apparently commemorating the towing of ships our of the canal):
I would appreciate your opinion on those items, some more information on the items' originality.