No, the platform doesn't support RDS Cluster Snapshots.

Currentl, the platform collects snapshots using rds:DescribeDBSnapshot: https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-snapshots.html whereas cluster snapshots need to be collected using rds:DescribeDBClusterSnapshots which the platform does not currently utilize: https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBClusterSnapshots.html

The result is cluster snapshots will not appear in the asset report.