90 gal construction question

So, I found a great deal on craigslist for a 90 gal "reef ready" with stand and hood. I ended up paying $100 for all of it.
The first thing I noticed was it only had one hole drilled in the bottom behind the glass overflow wall, so Im gonna half to run the return up and over. looking at the hood it was designed that way with several holes in the back of the hood with plastic grommet rings to protect the wood.

but the hood is trashed no big deal I planned on building a nice new one anyway,so I cut the old hood off, it was siliconed down, and thats where I found my question.
This tank has no horizontal braceing at all. completely open the way across

The tank is half inch thick glass, but I was wondering if this is normal on a tank this size and thickness ?
thanks

 

It could be my 75 has 1/4" thick glass with a brace. For 6" taller it would only need 1/8" more thickness.

 

my 90 has no center brace, it came that way.