Probably. Figure that water weighs around 8 pounds per gallon and subtrate may be even slightly heavier.
If you figure around 160 pounds for the tanks contents and around 40 pounds for the tank. If I were you I would lay a board on top of the TV stand and place a barbell with 200 pounds on top of it. Don't go hog wild shaking it all around, but gently nudge the barbell side to side and front to back. It the stand feels sturdy to you with the 200 pound barbell and you gentle movement of the weight on the stand, then you are good to go for a delicate aguarium.
The downside is that you could crush the TV stand and feel like a reel dummy, but it is better having dead weight crush the thing then a tank of fish which you would also lose in that case.
If you do not have the weights you can probably use you body weight to determine the stands strength. Just be careful not to break your backside!