Plus I noticed a big gaff withe the Starkiller weapon as the rebels approach… there is no beam being sucked in. Oops.
The weapon charges in a different area. we only see the actual weapon section when they arrive
There isn’t much in the film to tell them apart, but you are right. The feed port must be on the opposite side. Just one more thing about the film that is unclear. I know Abrams like mysteries, but he left too many things unexplained that the film needed.