What does the SSN-23 even look like in relation to SSN-21 and SSN-22? The Jimmy Carter is to be a special operations boat along the lines of the Parche SSN-683 which is expected to be retired from service in one to two years. Has the SSN-23 even been launched yet? Due to its highly classified missions it is being tailored for, does 'Viking' even really know how this boat will actually appear? If it is even half as interesting as the Parche is likely to be, it will be a mind blowing design in bold advanced technology.
I don't want to put the model down your so hot to get.... but I would suggest saving your money, keep your power dry and keep your eyes open for a future model kit that might even remotely hold any promise of scale accuracy. The person that bought the model on ebay will likely be using it as a desk paper weight in a few years when a more accurate model kit appears hopefully. What Parche is rumored capable of doing would make 007 seem pathetic. As Arthur C. Clarke is quoted as saying...."Compared to Science Fiction....the Truth will be even more stranger."