I know that for older versions of .NET, you can determine if a given version is installed by following

https://support.microsoft.com/en-us/kb/318785  

Is there an official method of determining if .NET Core is installed?

(And I don't mean the SDK, I want to check a server without the SDK, to determine if it has DotNetCore.1.0.0-WindowsHosting.exe installed on it)

I can see

HKEY_LOCAL_MACHINESOFTWAREMicrosoft.NET Cross-Platform Runtime Environment.NET Framework 4.6Win1-rc1 

with Version# of 1.0.11123.0 on my windows 7 machine, but I don't see the same stuff on my Windows 10 machine.