It depends how it was lowered....
I did mine with the Eckelers lowering kit on the front.
which you can't easily reverse, it involves removing the front spring
and sawing off the blocks and replacing the blocks with smaller units
in the kit. And the rear just involved longer spring bolts with a long
threaded
end with nylock nuts. That's easy to change back...

If you are dragging really bad, I'd say it been lowered more than normal.
BUt understand even a stock Vette is very low, and prone to drag the rockers
and spoiler over speed bumps and such.