Heh, depends. I do believe they *may* made differently, but interchangeably. I've got several M401 attys that are different from one another, or seem to be slightly, looking at them.
All EVO attys I have seem to have a slightly wider mesh wick, but look similar. I'm unsure still as to differences in
vaping on each, though.
I did note I can go to 10 second inhales without cutoff on most, but not all, of my M series batts, and all my EVO batteries.