For what it's worth, here is a Damascus hammer gun with Briley chokes:

http://www.willoughbymccabe.com/d.php?gid=890

Teague will install chokes on Damascus barrels apparently as well. Probably not worth it on a low grade gun obviously.

"We can even fit multi chokes to Damascus barreled guns."

http://www.teaguechokes.com/teague-multi-chokes