ora2pgpro does not allow to import data and to only apply changes after the first import. But you can use the --cdc_ready option to export data with registration of the SCN at the time of the table export. All SCN per tables are written to a file named TABLES_SCN.log by default, it can be changed using -C|--cdc_file option.

These SCN registered per table during COPY or INSERT export can be used with a CDC tool. The format of the file is tablename:SCN per line.