oceanic should warranty the tank if there was a problem. I would give them a call and inform them of your concerns. That way if a problem should arise in the future, then they would be aware of it early.
This was our old tank, and if I recall, those bubbles have been there since we had the tank set up, 2+ years ago. Since we never let the tank set dry, between when we stopped using it and it was picked up, that should have helped maintain the integrity of the silicone seams. We know how larger tanks don't always do well when left to sit dry for extended periods of time. That was why we took the extra effort to keep it wet/filled (to about 80%, about an inch below the bottom of the overflow). So I am not sure of how much concern they would be, but it doesn't hurt at all to contact the tank manufacturer about it.
I am pretty sure I remember what you are talking about, but it has been a while since I saw it empty (and clean ). I am 90% sure that what you are talking about was there when we bought it, but it is still best to contact the tank builder directly