Josh, I don't know of any official vendors. I've always refurbed my collection myself. I just finished my work helmet (N6A-Sam Houston) and it came out great. All you need is some sandpaper (I use 100 grit or finer), a water soluble/non petroleum paint remover, Sherwin Williams gray primer & a Sherwin Williams top coat i.e. gloss black, gloss yellow, etc..
If you do it yourself be careful sanding near the scroll design on the brim and don't use anything that may gouge or puncture the leather.
Dean-o