NX Mixed units with new part, preference dialog vs. customer defaults

Some users are not seeing any entry for the following preference nor is there any dropdown selection option:

In the Customer Defaults it is necessary to set the Item name (db_part_name) and not the Item number (db_part_no) for the Customer Defaults -> Teamcenter Integration for NX -> General -> Parts without NX Datasets -> Default Seed Part. This will need to be entered manually.