In the CZC description, they will mention needing a #47 drill bit meaning the sight is not notched. CGW's sights from Dawson are pre-grooved. CZC does have quite a range of sight heights but a little conversion is needed. Both are quality sights. If you do drill, drill from the left to the right as others have stressed. Finally found (with help from my cat) everything I launched, put it in my SP01C and will take it to the range mid week. For this mod I put in CGW's SRS2 with the 11.5# spring, left out the lifter and its spring, put in a old 85C trigger with RP-TRS, the Floating trigger spring and CGW's bushing. Also I am modifying an 85C with similar parts and it should be ready by Friday.