My 165g is 1/2 inch thick glass and it is double braced.
What are the dimensions? It looks to be 4 feet long, there's no way a 150 is that short and that deep it would have to be far too tall to make up for the volume
That's a good score - but, it's a scary tank - I would never have anything like that without a brace - even if it was built without one. I'd put one on. Why risk it, right?