MD'ing enthusiasts hunt in sod all the time. Parks, schools, lawns, etc... I can't see why yours would be any different.
If the signals/coins are shallow (easy loud bongs) then probe them out with a screwdriver. When done, ruffle up your spot, and presto, no hole or mess.
For deeper ones: assuming the soil is moist, just cut a plug (be sure to keep the maximum amount of root-ball intact). Turn the plug upside down, and fish into the soil in your hole. Use a rubber catch mat so you don't make a mess with the dirt tailings you pull out. A sunray pinpointer is a BIG help

After finding the target, then put your soil back in the hole, put the plug back on top, and stomp it back in to place. Ruffle up the surface with your fingers (to scatter any crumbs, and ruffle the grass to stand back up straight, and PRESTO, no hole
The "stomp" on the plug part is very important. Because if you don't the plug tends to sit a tad higher off the ground, and dies, etc.... So be sure to stomp it back in place tight and low, when done.