Presumably, this is going to be a workhorse, so you're looking for straightforward, functional items.
Stem: do a search on eBay, etc., for a silver ahead stem, see what it throws up, and choose something of the right length and angle for you. If you want a Specialized stem, you could put a wanted post on here. Silver would look better than black on this bike I think.
Saddle: very much a personal choice. I like a Madison Flux or Charge Spoon myself. I don't find the faux leather survives the elements very well though (barely a year before looking tatty), which is pretty wasteful, so I bought a cheap Halfords saddle with a two year guarantee for my all-seasons, all-weather RockHopper. It's almost as comfy as the Flux or Spoon and seems to be holding up well so far:
https://www.halfords.com/cycling/bi...97*MTY4OTc5MTM2MS4xLjEuMTY4OTc5MTM2NS4wLjAuMA.