One would think a bunch of privateers would be lucky to scrape together what parts they can. so the idea of two
additional deflector dishes seems a bit unlikely. More likely they found a more or less complete Saladin- or Hermes-class scout (whichever is the one with the dish hanging from where the planetary sensor usually sits) and simply moved the lower neck and warp nacelle to the top rotated 180 degrees, hence the upside down nacelle.
Other than those minor nitpicks, though, I do love this design and backstory. Keep up the good work!