Greetings from Germany!
If I found the right pictures on pinterest, then the model is based on a paper model named
"Emiliana" or "Emiliana Torrini".
A very similar paper Model:
"Maly Modelarz 1998-10-11 - Emilia"
(from a polish series, instructions in polish but can be built without learning the language ;-)
I have both paper models (and quite a few other similar coasters in my "little" collection of paper models and plans).
For details send me a pm.
No Info about the prototype yet, but I will dig through my archives.
Best regards and greetings to Canada, quite some time since I've been there,
OK, here is the prototype:https://www.naszbaltyk.com/wszystkie-kategorie/historia-artykuly/1731-kabotazowce-typu-kz-450-flora-i-emilia.html
And I found the plans, too.