Redirect Micro sites, alias sites

micro site in .co.uk domain points to the alias site in .com domain,if we write this code in ".htaccess file" of .co.uk. Will it work . Code is given below-

Code:

Options +FollowSymlinks 
RewriteEngine on 
rewritecond %{http_host} ^abc.co.uk [nc] 
rewriterule ^(.*)$ http://www.abc.com [r=301,nc]

Are alias sites considered as duplicate content sites.