I saw a sign that reads: entering land managed by Idaho Fish and Game

On Clear Lakes Ln in Buhl just west of of 1500 there is an access rd with a chain and sign that reads entering land managed by Idaho Fish and Game. I believe this rd leads to an old abandoned shack that you can see coming down the Clear Lakes grade. My son and I would like to go metal detect around that old shack but don't want to do anything illegal. Is that something we are allowed to do. The sign did not say anything about keeping out or no trespassing.