Like everything in dealing with natural substances, the answer is--it depends on the individual pieces of wood you are using. They're all slightly different. Some stocks and RR's will match perfectly with the same treatment, and some will not. Some times they require slightly different treatments to get there.
You just have to experiment ahead of time with scrap from your stock blank. If you don't have stock scrap, then start with some generic wood from the same species, and then your final experiment in the barrel channel where it won't show.
The trick is in controlling and applying the variables of finishing. For instance, in using AF or FN there are several;
Pre finish preparation and treatment
AF/FN concentration or carrier (alcohol vs water)
Heat treatment (time, temperature)
Neutralization chemicals (ammonia, baking soda, lye)
Post AF/FN treatment (sand paper, steel wool, scraping)
Stain(s)
Post stain treatment (sand paper, steel wool, scraping)
Final finish
The key is to experiment first, and even then when applying things to the final product it's a major "there's no going back now / pucker factor" moment in the build.