Winchester Supergrade inletted slig swivels

[cvarcher]

I love these swivels and would like to mount a set on my Henry Single Barrel Shotgun. Talley sells them and it includes 2 plates and 4 screws. 2 screws are pointed wood style self tapping .But the other 2 look like bolts with a flat tip and finer threads. Are these for the thinner foregrip where possibly a sunken nut and washer is embedded in the barrel recess of the foregrip?? It didnt come with any nuts? I dont see how these fine threads would hold into the wood by themselves.