I doubt prices will drop that much on most of the stuff. The prices on many pieces was not that much less before the ban. Torches are about the only one that really increased a lot.
If the ban gets lifted obviously most vendors will still push the higher prices, but that will only last if people will still buy them at high prices. If less people pay the 1200$ for a HG then the vendors will forced to lower their prices at least a little until people start to pay the price.