It actually prevents a person from possessing ALL firearms. PC 1210.1 (aka Prop 36) does not restore firearm rights, and a person convicted for a felony drug offense and receives relief under this section is still prohibited from possessing firearms under California and federal law.
You are prohibited from possessing firearms (and ammunition) under California law because this section still allows you to be convicted under "under Chapter 2 (commencing with Section 29800) of Division 9 of Title 4 of Part 6" which is California's firearm prohibited persons section.
Because this section does not restore firearm rights under California law a person is still considered prohibited under federal law too. 18 USC 921.
Michel & Associates
You've discovered a distinction in the text that is overcome by the reference to PC 29800 which prohibits anyone ever convicted of a felony or who is addicted to a controlled substance from every owning or possessing ANY firearm.
So the short answer is yes, Pc 1210.1 does prohibit someone who has had a felony PC 11350 conviction set aside from owning or possessing, etc., a firearm.