Um, Just looked at the Taylors sight & I see where they offer the .45 Colt chambering but not something spacific for the .410 chambering although you can load a .410 into a .45 Colt chamber.
Like Deadguy stated, I'd just save my $$$ & just load the Percussion cylinder with a healthy shot load.
I know that my 60' Army & my 58' NMA's will take a load of:
15gr. FFFG Goex.
piece of cereal box for over powder wad.
15gr. #9 or #7 lead shot, this is using the same measure that the powder was measured with.
piece of cereal box for over shot wad.
compressed melt candle wax over the wad to help it stay put.
Cap & it's ready for some Snakes up to 5 yards.
With the Walker you may be able to get 25gr./25gr. or maybe close to 30gr./30gr. in those massive chambers & substitute the shot for something like #5 or #3 as well for more of an effect but just remember even if you did get the cylinder & used the .410 in them or loaded the chambers like I mentioned this will only be effective for maybe 10 yards MAX because of the effect that the rifling plays on the shot as it goes through the barrel.