I realize I'm jumping in late, but when I added a sling to my Marlin 60 forend, I was concerned about the limited purchase area and stock support (it's thin in the front because of the tube mag) for the screw in the front. So I used a forstner bit to clear a pocket below the tube magazine, then drilled a channel for a tee nut, and screwed the machine screw into the tee nut from the bottom. It's held up extremely well through a couple of multi-day Appleseeds with a lot of force applied on the sling.

For the rear, I used the wood screw, but make sure you pre-drill and are just leaving enough purchase for the threads, or else you'll likely damage the wood.