Just for the record; this model has now been officially attributed to Erkkitapio Siiroinen in the catalogue published this year for the exhibition of his work in Riihimäen Lasimuseo.
They mention since the Riihimäen Lasi 100 years book was published (with a catalogue of Siiroinen's work) they had found some photographs to be able to identify a couple additions, this is one.