In MarcEdit
1-Make a new 001 field:
Delete the incorrect 001 fields using Add/Delete Field
Go to Tools; Build a New Field:
=001 {035$a} ← 2 spaces exactly in front of curly brackets
2-Go to Tools; Edit Field Data:
Field: 001 Find: (OCoLC)
Position: [blank] Replace: on
Save
...
If you MarcBreak it, you will see the lovely prefixed 001s
Close MarcEditor
Tools; Merge Records
Source file: the oclc records
Merge file: the GPO pilot project records (with deleted 001s)
Save file: the new merged file
Next
Select the 001 field only
...
Edit records
Would you look at that!