Unique separates records according to the fields you select as a key. U returns the first record for each key. D returns the additional records with the same key. Selecting every field asks whether entire rows match; selecting Worker asks whether the worker identifier repeats even if another field differs. The output is sorted by the selected key fields, so add an explicit Sort when a later step requires a business order.
Record ID adds a sequential identifier to the incoming stream. That number helps trace rows, but it doesn't prove that two source rows describe different customers or workers. Generate it after you decide the intended record order. A starting value other than one can be useful for a handoff, and it must be applied consistently to every record.