An instrument guide assembly for a bone plate includes an insert configured to be arranged in a hole of a plate member, the insert having a through-hole, and a guide member separable and positionable through the through-hole of the insert, the guide member having a head portion, a shaft portion extending from the head portion, and a guide channel extending through the head and shaft portions for guiding a drill or other instrument therethrough. The insert is movable axially relative to the guide member from a first position at an end of the shaft portion opposite the head portion and past a first stop to a second position at the head portion. At the second position, the insert remains axially movable in a limited range between the first stop and the head portion, while the first stop prevents the insert from moving back to the first position.