Page "AMSAT" Paragraph 19

Most amateur satellites do not receive their sequential OSCAR designation until after they are successfully in orbit, and then only at the request of the launching organization.

Regardless, amateur satellites will have been named by the organization that constructed it, and that name is frequently prepended to its OSCAR designation, resulting a name such as CubeSat-OSCAR 57.

In conversation, names are usually abbreviated as CO-57 or similar.