It looks very much like a Weltklang and I believe it is. This is your example see below for a number of Weltklang examples.
They have had several types of distinctive keywork but they did have this LH plateau and those palm keys.
With due respect for all the Wetklang soprano owners , in my not so humble opinion :twisted:, they are not worthy of the good Dolnet name! The same goes for Berg Larges, another of the MANY stencil names of these Weltklang sopranos. I can't understand why they chose to have Berg Larsen sopranos made by Weltklang, but they did.
There was a curved Dolnet soprano made by Orsi but the straight ones ( at least this in the ebay listing) were made by Weltklang
It will probably struggle to fetch the minimum price of $300.:|
At some stages in some models there was also the bulge on the neck but this disappeared later on. Your example in the ebay pics (and all the other ones that I've quoted here below) has the distinctive bulge too.