With it being so cheap that kind of clues me into believe that they basically used the ND-2500A architechture and didn't have to redo that much. I guess that's why the dual-layer capable firmware has proven to be pretty successful thus far.
Great price though! Most likely when I build a new computer this summer it will get one of those burners put in and maybe the LG that supports Dual-Layer and DVD-RAM. Always nice to have extra options.