Doesn't look like Apple's going to release AST 2 or an equivalent, instead requiring users to contact Apple Support to get the pairing done.
> A System Configuration step may be required at the end of your repair. System Configuration is a postrepair software tool that completes the repair for genuine Apple parts. The repair manual will indicate if System Configuration is required. You will need to contact the Self Service Repair Store support team by chat or phone to initiate System Configuration.