How we can we know SQL Replication components installed in SQL server
You can us the below T-SQL command to query the registry and confirm is Replication Components are installed:

USE master;  
GO  
DECLARE @installed int;  
EXEC @installed = sys.sp_MS_replication_installed;  
SELECT @installed; 


if @installed = 0 then replication is not installed. That stored procedure actually reads the registry using the below command, which is another way of checking:

EXEC master.dbo.xp_instance_regread 'HKEY_LOCAL_MACHINE',   
        'SOFTWARE\Microsoft\MSSQLServer\Replication',  
        'IsInstalled'


sp_MS_replication_installed example

Underlying code