If it is truly a 500 SEC, then the car has considerably more value (relatively speaking) than a 380 SEC that has been "badge-enhanced".

FWIW - if it is a 380 engine, I would pass.
If it is a 500 (which it most likely is) then I agree with the advice given by others.

The good news for you...
There are lots of sources for interior parts [and engine:mechanical:exterior for that matter :p :p ] (new/used) that can be found to improve the SEC's condition.: