My first thought was yes, that is erosion. The flame cutting tends to back that up.
Maybe I'm an idiot but I knowingly bought a 629 with forcing cone erosion and flame cutting for a shooter. Flame cutting never gets deep enough to effect the revolver's functioning. They keep on shooting well with quite a bit of cone erosion. However, if I could not handle it I'd assume that it needs a tune up, meaning stretching the yoke and installing a fatter hand. The biggest risk with a revolver that you could not handle would be a previous owner filing the rear end of the barrel when they should have stretched the yoke or installed end shake washers. That would require a gunsmith to set the barrel back a revolution. I could handle the one I bought and the price reflected its condition. Without being able to handle it I'd pass.