First of all you are a newbie on here , so the *He* you are talking about is most likely You. And the price is a sad joke. If you are replacing the fittings and faceplate on existing housings it is MORE work than a standard retro, because you cannot build the parts in advance. You have to take the old one apart and rebuild it piece by piece.
This is CABL.com posting #137251. Tiny Link: cabl.co/mJRT