They’re to put stuff in! 
OP - what sort of brown are you looking for? If the ones you find are too light - they’ll darken up with oil (try a hidden spot first to see how it looks)
I had a devil of a time finding brown spur straps and a kind COTH’r took pity on me and sent hers.
Then I found them for sale everywhere - d’oh! :uhoh: How silly of me. But I still have those spur straps.
The final arbiter is always your hunt Secretary (or Master whoever makes those decision in your club). For example - though tattersal or canary vest is the “traditional” turnout - my hunt club permits members with colors to wear a dark blue vest. It’s part of our livery. It’s little things like that which can vary from hunt to hunt.
If you have your colors - buy a nice frock (with the correct number of buttons and type of corners) have it tailored if necessary, and enjoy the longer length and different cut when it’s freezing out. You can buy them used if you want, and there are different weights to suit the local climate.
Are you referring to a game or hare pocket, by chance? The whistlepocket is small and right at the seam, but there can also be a hare or game pocket. I always thought the whistle pocket was for a whistle (to be used by a downed rider or rider needing assistance) But… I really don’t know.
As you can tell there is disagreement over the wearing of frocks by members without colors. Brits think Americans are nuts.
Americans don’t have many centuries of tradition and culture to draw on so we’ve created our own over time. Tell you what - when you hunt in the UK do what they do. Hunt in the US - do what the club tells you to do. Can’t screw up that way. Well - you’ll still screw up on something but you’ll look fabulous so hopefully no one will notice. :winkgrin:
Happy hunting.
