Partly right, at least up to Napoleon. Said capital's hinterland, let's define it as Cisleithana, shall we! did include all of modern Austria (well apart from the Burgenland), however, modern (German)-Austria doesn't include all of these hinterlands even if those being divided by language lines (ever heard of South Tyrol, the Sudetes, Brno and Maribor?). Not that I want to undertake some good old historical revisionism here (quite a strong case could be made for South Tyrol though, if people wanted), but just pointing that out.
I was mostly being facetious, but can you really argue that Tyrol counts as Viennese hinterland? Or even Styria for that matter, though of course only parts of both historic provinces are even in Austria today.