When you install the update, make sure you change the default pathname the installer shows to the one where your Bryce 6.1 is installed.

Once 6.1 is installed, you should not have a separate copy of B6 installed on your machine. They don't play well together.

To see the version installed, you should see Bryce 6.1 in the header bar at the top of the program and when you press Cmd/Ctrl and choose Help > About from the Menu Bar, the popup will show version 6.1.13.1.