I won't bet against you.
They can’t produce a narrow interpretation limited to DC. Currently there is a conflict between appelate courts, with the 9th Circuit ruling in favor of a collective right, while the 5th Circuit ruled in favor of an individual right.
The Supreme Court needs to produce a ruling that will apply uniformely throughout the US.
I suspect, though, if DC loses, they will just write regulations that will produce the same effect as a ban and just start the process again from scratch.