The Crown/Samducksa SDL-301-DX round restrictor plate offers the authentic round control most common to Korean levers. It replaces the current octagonal gate found in the lever, which is the default install for it.
To replace the original SDL-301-DX gate, simply remove the 8 screws that hold the restrictor in place. Line up the round restrictor plate in the same orientation as the original plate, and replace the screws. Note that lifting the gate and screws together may result in repositioning the microswitches. Take care to completely remove the screws before lifting the gate.
You do not necessarily have to remove the battop or e-clip to remove the restrictor plate.