Dumping timeseries collections is no different from regular collections. There are some differences in the dump output, but we may not want to go into that since we don't really go into depth on the dump output in the docs. Dumping a timeseries collection will output a metadata file for the timeseries view and a BSON file for the system.buckets collection. It is impossible to dump the system.buckets collection without dumping the timeseries view.
Something that we definitely should mention in the docs is that you can only use --query and --queryFile on a timeseries collection to query the metadata field. You cannot query the data itself.