No, these numbers are not OCLC numbers.  The numbers in the 001 field are OSTI ID numbers that can also be searched in OSTI.GOV.  To avoid conflicts with the OCLC numbers used in library catalogs, the OSTI ID number in the 001 field is preceded by the letters “OST.” Some loaders for library catalogs strip out the leading letters found in the 001 field.  If such a loader is used with the OSTI.GOV MARC records, unrelated records may be overlain.  It is possible to leave in the leading alpha characters and add a number to the string to allow the system to import the letters.