Looks no thicker/thinner than my 1/2" glass 8' 240. What you want to be worried about is the sides of that bead and water under-cutting it and getting into the silicon between the actual glass. As previous poster mentioned, the inner silicon seal is only there to protect the actual silicon holding your tank together (stuff in between the glass).
Basically, as long as that bead is water-tight and not peeling on the sides where water could contact the true seals holding the glass together, you are fine. I also agree that thicker near the bottom is going to be more important than being uniform.
Are the inner seals original from tank build, or a re-done at some point?
I would be more worried if it was re-done at some point and the person doing it used GE silicon I or some other cheap non-aquarium stuff.
If you re-do it, go with Momentive 103/108 (Black / Clear). Can order it online from granger.... More expensive, but you get what you pay for.
Its not too much work and with some cheap caulk stripping tools, acetone, and some painting tape to mask it, you will know the seal is new and will hold for a long time. Just make sure to pull the tape as soon as you smooth the bead with your finger (use a latex glove).
But at first glance, your seals look fine...
