I don't think you have to go through all that, just see if the male radius of the shoe matches the female radius of the drum.

This is really a very rare problem in this day and age. Back when local shops would rivet new linings on shoes, it was common to arc the shoes to fit the drum inside diameter. I'd be pretty surprised if this was a problem on your coach unless someone installed the wrong shoes and that should be pretty apparent just by pulling a drum and laying a shoe up against it.

Even then, I'm not sure that the shoes not having a correct arc would effect your pedal. What typically happens is that the shoe doesn't have full contact and therefore more PSI where it does have contact. The shoe wears down in that area pretty quick and 'arcs' itself. I recall back when I was a pup that the conventional wisdom was that shoes needed some time to 'bed in' before being put in hard use.