Maybe it's just me, but in the first picture one of the shoes looks to be missing a fairly large chunk of friction material... I'd be a bit worried about that!
Looks normal.
Friction material is often offset around the shoe. With normal rotation of the wheel, one shoe tries to grip, a self-servo effect, called a leading shoe, the other is pushed off by the rotation, so a trailing shoe, needing more effort to do any work. The offset lining is deliberate but I've forgotten the science.
In the pic, if we assume that is the left rear, the shoe nearest us is the leading shoe. The rotating drum tries to pull the shoe harder into contact. The rear shoe gets pushed off by the drum. The differences give a smoother more progressive application.
With front drum brakes, except for the very oldest cars, they are twin leading shoes, so two wheel cylinders. Both shoes are leading, giving the self-servo effect, helping brake effort.
When reversing, the leading shoe becomes a trailing shoe, requiring significantly more effort to give any reduction in speed. For this reason, rear brakes are always single leading shoe, as just the single leading shoes on each side do most of the stopping. If all shoes were leading, stopping in reverse would be mostly by hitting things. When reversing, you will notice that it takes a significant effort and more time and distance to stop. Discs on the rear help a lot, but are more expensive to fit, so we don't get them on mid-lower range vehicles.
I'll stop now, before we all lose the will to live.
