Well, I confirmed it.
Right now, the collection is not on display anywhere. After being taken off its former location in Montjuïc Castle it was put in storage, and there remains. Institutions and particulars have been reclaiming the items that were in deposit, and a relocation of what remains of the collection in Figueres will have to wait for quite extensive (and so far without funds) reformations in the new location.
In short, the collection of Barcelona's Military Museum in Montjuïc is no more. And will hardly be again.