RDS import from SQL backup
Yes you can restore native backups and AWS has gone to the trouble of writing a very complete tutorial on how to backup from and restore to a RDS SQL Server instance.


restore backup

exec msdb.dbo.rds_restore_database 
        @restore_db_name='database_name', 
  @s3_arn_to_restore_from='arn:aws:s3:::bucket_name/file_name_and_extension';


There are some limitations to keep in mind and they have explained them all in detail. Some of those limitations are database size, and the types of instances you can restore to: The micro rds sql server instance for example doesn't support restores or backups.

Also keep in mind the difference in versions between what you have locally and the RDS version you are restoring to. Amazon offers SQL Server 2008R2 and up. 

https://aws.amazon.com/rds/sqlserver/

Craig