Excellent! Thanks for the visual reference!
OK, if you want the upper and lower receivers and the buffer tube to be FDE also, your best bet is to:
A) Start over. Buy FDE finished factory AR, or AR parts.
B) Refinish them. Either Rattle Can as suggested above, or Cerakote (if you can spend the money, and want it to stay pretty for a longer time).
For the other stuff, lately I have used Primary Arms as my go to site for AR parts. There are other places I shop if they don't have what I want, but they have good selection, prices, and ship fast. And they have taken care of me on the occasions something hasn't been right.
That stock is the VLTOR Emod I believe.
If you want it all to match, Cerakote is the best option.
Thank you very much for helping a pantywaist.