Yep that is a combiner box, it should have breakers inside to allow connection or dis-connecting of the solar panels. Here is a guy setting one up. It appears to be a Midnite box and might be the same box.
If the array is not going to be used and There isn't going to be some big squabble. I'd spend an afternoon and just disassemble the whole thing, and load up a truck, trailer or camper... You will likely need a combiner box. Likely your old system was a 48 volt battery bank. MPPT charge controllers like to have input voltage around 2x the out put voltage, if you are running long distances, higher voltage can be desirable, there is less voltage drop and the corresponding loss of power if lower current and higher voltage is run long distances over the same size wire. Some of that reasoning that higher voltage system run 'easier'.
While you may not want or need the extra panels now, they would be nice to have for the future home or cabin you'll be building. I have 2700 watts of panels that fit easily in the closet of a small bedroom in the tin can (mobile home). So even if you have no space for them, it's likely you can find some friend to store them for you. Remember they live outside some just a couple square feet or space in a shed or barn.
Once the breakers are off, there will be no current on the panel side. This should be a one way street and no current should flow out to the panels unless something went amiss in the fire. Once the breakers are thrown I would feel very safe in disconnecting the panels. I would also take the breaker box if possible, it'll save you a few dollars shortly down the road.