The Restoration gave way to the location of the Hourglass. And Sloane didn't know about the Restoration. Conrad had it in his possession and he could have easily given it to Sloane, but he didn't, for one reason or another.
Conrad showed Sloane part of the restoration, but not the whole thing. However, in season 3, Sloane appears to be well aware of the Hourglass even before the Restoration came to light. Therefore my theory . . .