I don't think truvue has made those aquariums in quite a while. I could be wrong. You may have a hard time using it as intended finding "original" replacement parts, like the skimmers they used to sell to go in the back. But you may be able to find a decent hob. I agree using it as is would be the quickest option to getting it up and running. Modifying the existing unit would to me be the next.
I'm not sure the easiest way to remove that chamber system. I'm sure it could be done but I don't know how. If it were glass it'd be simpler just cut out the silicone, but being acrylic I'd guess cut the acrylic and sand down the edges. I've not had alot of acrylic experience. I buffed out a 300g acrylic tank, that was a lot of work. I built an acrylic sump with help from a friend who made acrylic products. I messed up one of the welds on the sump. My friend was able to remove the panel using the weldon to loosen the two pieces but they were only minutes old. I don't know if that works on something that has been assembled for a long period of time.