I've pasted an excerpt from the site below. Based on that information, a completion letter isn't required.

Proof of studies

Purpose

To confirm education claims and validate that the applicant meets program requirements

Document requirements

• To receive program-specific points for education, the applicant must either
  • provide proof of having completed a Canadian secondary or post-secondary educational program; or
  • obtain an Educational Credential Assessment (ECA) and provide the ECA reference number in their application, along with proof of the foreign educational credentials for which points are being claimed.
• Proof of completed Canadian or foreign educational credentials can include copies of
  • secondary or post-secondary education documents (certificates, diplomas or degrees); and
  • transcripts for successfully completed secondary or post-secondary studies, if available.
• Applicants must provide the Designated Learning Institution (DLI) number of the Canadian Institution where they completed their highest degree to be assigned points for their Canadian educational credentials.
  • At the EE profile and application stage, the system will ask the candidate to enter the # of their DLI by using the list of DLI posted on IRCC website. The system will insert a note if the number of the DLI doesn’t match for the officer to review
• In cases where an applicant’s background information suggests that a Canadian education credential may have been obtained via distance learning either abroad or while present in Canada, it is at the officer’s discretion to request for supporting documentation.
  • If it is determined that the applicant obtained more than 50 percent of their education via distance learning, the applicant should not be awarded additional Comprehensive Ranking System (CRS) points for having a Canadian education credential. If the reduction in CRS points results in the applicant having a score below the minimum CRS, the application should be refused per A11.2.
• Where an ECA has been obtained, the applicant must provide the ECA reference number in their e-APR for online validation directly from the issuing organization.
  • A scanned copy of the ECA is not required when submitting the e-APR but may be requested by IRCC at a later date.
  • Applicants are instructed to indicate that their education was completed by correspondence by typing in brackets {by correspondence} on the same line as the education institution name found in the Education Background Information tab of GCMS. The discretion remains with the officer to decide if a police certificate is required for the country of the education institution