The VeePeep mates to the dovetail by sliding a small piece into the dovetail provided with the vee peep. this piece is drilled and tapped allowing the veepeep to fasten too it. this is both for the rear veepeep and the front sight.
I know this doesnt explain it that well but i have installed the veepeep on my lyman gprs, tc renegade and tc new englander.