What was the family name?
Do you have records from Russia that indicate "this was never the family name"?
Anything is possible, it was not uncommon for immigrants to "share" passports, as until c. 1920 passports did not contain photos. You can be certain the COA is for the person listed on the manifest as on July 11, 1924 a check was done to ensure that he had been in the US long enough to apply for Citizenship. Also the COA number 1600C-31994 was recorded
Croatian Heritage Museum