839.1103—If my qualifying retirement coverage error started when I should have been placed under FERS automatically, but my agency put me in CSRS because I had some past service, will I get a C

No, employees who should have been automatically placed in FERS (generally because they did not have 5 years of past service under CSRS rules) do not have a CSRS component in their future FERS benefit. All service must be treated as FERS service in this circumstance.