How are we supposed to give you a definitive answer? All we can tell you is look it over, see how it's built, and test it out if you think it's sturdy enough.
Honestly, a lot of the wood stands that LFS sell with their tanks are not well made. I bought my first tank/stand combo recently for a 90g bowfront, and I looked at the stand like, really? This is going to hold up 1000 lbs? I made a table in grade 9 with more structural support.
Yet the warranty states, if the tank malfunctions while on a stand OTHER than one of their own (shitty) stands, it is void.
Since the dresser is low to the ground, that's a good start (especially for bigger tanks). 6ft long, how many legs does it have? 4 on the corners and 2 in the middle? If it doesn't have support in the center, I wouldn't put anything too weight bearing on it as it would most likely bow over time.