I don't know. From the photos, they're two lines of bucked rivets level with the edges of a lowered awning. This seems to be accentuating them.
Normally, these rivets can cause slight dimples as the aluminum is pinched into the butyl tape, which has a little give. Check the interior rivets, which are not quite as strong as the exterior rivets - if there's some structural issue, it may well show up more clearly inside than outside in some cases.
It's only if the dimples a deeper, and others here can testify what a normal dimple is, would I be particularly worried. This is within the realm of what I have seen on healthy trailers, but it is undesirable to some.
I am not an expert. Opinions and feelings vary.