There is no cluster specific showrev command that will show what is installed on the individual nodes of the cluster. (This is a generic problem, not just Calendar Server specific. You would run into the same difficulty with any product installed on a global file system.)
This is a problem when you want to update Calendar Server. You need to apply the patch to every node where Calendar Server was already installed. In addition you can’t apply the patch to a node if Calendar Server hasn’t already been installed on it. If you don’t know which nodes have Calendar Server installed and which do not, at the least, it will be confusing and cost you time trying to discover where Calendar Server is installed.
Workaround: Run the following command to see all of the nodes where Calendar Server is installed: pkgparam -v SUNWics5 | grep ACTIVE_PATCH