Darkthunder has a point and i was a bit shocked to hear that the station was already that old. I mean if you watch the station in voyager, the hull doesn't have any resemblance to the old stuff, i believed it was 2350'ish... Could be another jupiter station or an older one..
Also, this is starfleet, i mean how many stations in starfleet were actually meant to have a defense against something and that you hear that its been wiped out by a single ship or so (or a deus ex stuff).
Or could be the station was indeed meant to upgrade weapons of other ships but that doesn't mean it has weapons of its own, there could be ships patrolling it or a few weapon turrets out there.
Also the jupiter station of voyager was a research post, no weapons upgrades. I think braga & co just messed it up again.