GUID must be the SAME on any computer.
To automatically register DLL on the user's computer run regsvr32 your_dll_name.dll in the command prompt.
Or regsvr32 /s your_dll_name.dll (silent mode) form the installer.
In this case registration data (especially ProgID and CLSID) will be the same as on the development computer.
There are also other ways to invoke automatic registration.
Just remember that auto-register function DllRegisterServer is built into your DLL.
/A new technology turns into completely outdated stuff before you have a time to read "Getting Started..." section.
/If there are some "system programmers" then others are unsystematic.