I've tried in the past to use the FED STD numbers to have paint mixed up for various projects. I gave my paint shop the FED STD numbers and the colors were off by quite a bit. Orange Yellow FS 13538, turned out more of a "Peach" color. It was explained to me that the pigments have changed over the years and the paint mix formula doesn't quite yield the same colors today. Don't know if that is the truth, but I know that I was not able to give the FED STD number to the paint shop and get the correct color.
So, what to do...It was recommended to me to go get the colors I wanted in model paint and spray out test panels, then take the test panels to the paint shop and have them scanned. This resulted in the proper colors that now matched the FED STD paint chips.
You could skip that step and just buy the FED STD paint chips and have them scanned, but I think my shop wanted at least a 6" x 6" piece to scan, and the little 1" x 1" chips were too small for their machine to give an accurate match. Things may have changed in the last few years, so check with your paint shop to see what they can work with.