Answer
Join the migration job's IC (Import/Convert) staging table against the actual target table/view on the shared unique business-key columns from your CSV data — for example, matching the staging table's key columns to the corresponding key columns on the real table lets a straightforward SQL join pull back that record's current ROWVERSION (and ROWID) directly, giving you the value Remove__ needs without relying on a dedicated RowVersion lookup function that doesn't exist for this purpose.