I just hit up the local Home Depot looking to find something close, nothing yet.
When I look at it, I think its close to bronze or antique bronze.

I have their gridlock, with the FDE accent pieces.

Its much more metallic and darker than Magpul FDE or Aluma Hyde II Magpul FDE.






Edit:

Doing more research.  the antique brass here is getting kind of close (# 13 in the grid)
but close up it looks too copper like.
https://www.rustoleum.com/product-catalog/consumer-brands/stops-rust/metallic/

This Champagne Bronze looks really close here (but compared to above it needs some more olive).



https://www.amazon.com/Rust-Oleum-313142-Preventative-Spray-Paint/dp/B072ZVVF39

That looks great.

Coming from an FN owner, you just need to learn to embrace your inner calico!