The first (quick) answer is that yes, buckets have their directory name to begin with "rb_" when they're replicated.
As for the missing TSIDX files, it may be possible to rebuild the bucket. From the CLI, you'd use something like splunk rebuild db_1479686070_1479451778_0_BF4B1947-4FB6-4464-BD62-299457B51B72 . This builds the TSIDX files (and *.data files - metadata) from the raw data journal, all afresh.
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