I recall reading that the edges of trimmed tanks are often unfinished (not polished.) I'd be concerned with cuts from sharp edges.

That said, I don't think I'd do it. 17 years in storage is a long time. I'd be concerned about the silicone degrading and any problems being exasperated by the removal of the trim. IMO, 90 gallons is too much water to take any uncalculated risk with.

But that's just my uneducated opinion - I'm a chicken when it comes to the possibility of saltwater on the floor (and everywhere thereunder.)