Marlin 1895 SBL is legal in California. When you see certain models advertised as being legal in California, that’s just a marketing gimmick. All of them are. It’s not a semi-automatic weapon, so it’s perfectly legal in California. At the same time, Marlin 1895 SBL has a barrel longer than 16”, meaning it’s a rifle and not an assault rifle. Therefore, no extra laws apply to it. You don’t need to remove any parts or add any enhancements to make it legal in California because it already is.