Regarding the use of leather on the walker loading levers, if they did not use something to hold them up I'd be surprised. I can't imagine putting up with such an annoyance during a battle.
I shoot two Dragoons (came after the Walker of course) which, even though they have a lever retaining device at the end of the barrel, occasionally drop the levers under recoil. Last weekend was the first time I shot these in a CAS match (I had them converted to cartridge cylinders for this) and the lever retainer on one gun jumped off the barrel. I had leather laces with me and tied up the lever for the rest of the match and it worked perfectly well.
Again, if they DID NOT use leather laces to tie up a misbehaving lever, I'd be surprised.