Yes, the chin gun is the forward mounted turret. The Dorsal turret is the turret on top of the ghost. However you were talking about the twin laser canons you claim are fired on the show. I've seen Rebel Resolve and went to the timestamp you mentioned and saw nothing, so...wait...why the hell am I arguing this!? Since when does this matter!? If you're a GM you can wave your magic GM wand and suddenly woosh it has twin laser canons!
The only Guns shown on the Ghost are
Top Guns
http://i.imgur.com/CLaoj31.jpg
Bottom Guns
http://i.imgur.com/2WyKIG9.jpg
http://i.imgur.com/mMguo04.jpg
http://i.imgur.com/JPjFT0b.jpg
http://i.imgur.com/ENLbuIW.jpg
http://i.imgur.com/SzujYIY.jpg
http://i.imgur.com/HqMyuAM.jpg
Please tell me how that bottom gun is just 1.
"Here endeth the lesson" - Elliot Ness to Al Capone in the Untouchables.
Edit: Added Many blurry action shots
Edited by GM Knowledge Rhino