The Lucky Charm thing was just a suggestion...

And yes, I have the higher barter/reputation... When my co-op partner asked how much gold I had (about level 12) and I told him, he was very surprised. Also very happy when I gave him considerably less than half of it, muahaha.

If you're really wanting to min/max (wouldn't advise it) then guerilla and 5 sneak will increase your damage output by +33%, so yes, it's a good call.