I've tried applying the same values to the corresponding Reader DC registry key and I'm getting strange results. The buttons do show up as a floating toolbar (labeled "Add-on tools") when in desktop mode, but they don't show at all when documents are loaded via the Adobe PDF Browser Control (AcroPDFImpl.dll).
Is there a way to get these tools to show when a document is loaded via Adobe PDF Browser Control? Also, is there a way to get them to show inline with the other tools? I have tried using related keys found in the Adobe Enterprise Toolkit Windows Registry Reference but with no success.