I'm not sure about Kobo but I think no DRM is not guaranteed on Google. For certain authors (e.g. John Scalzi) their books on Google will have the small part in

I'm not sure about Kobo but I think no DRM is not guaranteed on Google. For certain authors (e.g. John Scalzi) their books on Google will have the small part in description says "At the Publisher's request, this title is being sold without Digital Rights Management Software (DRM) applied." (e.g. https://play.google.com/store/books/details?id=XVwOEeHTU4QC https://play.google.com/store/books/details?id=XVwOEeHTU4QC) but my understanding is without that statement the book will be with DRM.