One of the most important things is not diving into a purchase. I've been there as well. I purchased a used 180g tank with a bunch of equipment. I drove 3 hrs away to grab it. I got it home and in place and I never did set it up. I never realized how many scratches there were at the time. The bigger issue were the sides had a bunch of coraline algae still on it. Although coraline algae is easy to remove, if it has been sitting there for a while, the algae will etch the glass. Thats where the problem was for me. I cleaned it all up and the sides were etched and cloudy.
I ended up selling it and went custom. Best decision I made because I love me setup now.
If the tank you purchased was rimmed and the glass is under 3/4" thick, I honestly wouldn't use it. The removal of a center brace on a tank that was not designed to be rimless can be a complete disaster. Especially with 180g of water running in it.