bases

These are on near perfect condition, the have been taken off my Police sniper rifle, 1 inch mediums, they held 7x50 meopta £60 plus post, or trade for 6x mag ,old Jap glass or European scope

I have a S&B rail scope mounted to a Tikka with apel two piece mounts. The bases are secured by a slotted knurled screw with a centre 3mm Allen screw. Are these two separate screws? If so is the centre Allen a "locking screw"? How tight should they be torqued to? I have read they can be over...