The plate fits following models. Mark I ? MUST confirm it has drilled/tapped holes Mark II ? MUST confirm it has drilled/tapped holes Mark II 22/45 ? MUST confirm it has drilled/tapped holes Mark III Standard Mark III Bull Barrel Mark III Competition Mark III Hunter Mark III 22/45 Lite Mark III 22/45 Target Mark III 22/45 Threaded Barrel Mark III 22/45 Bull Barrel Mark III 22/45 Hunter Mark IV Standard Mark IV Target Mark IV Hunter Mark IV Competition Mark IV Tactical Mark IV Hunter Mark IV 22/45 Lite Mark IV 22/45 Tactical