1) It is optional. abs32 is the addressing mode. The linker addresses this section with 32 bits. R is also optional, and this indicates the access type for the section, in this case read. If you want to learn more about this, give a check to the MCU_Kinetis_Compiler.pdf in your CodeWarrior installation:
C:\Freescale\CW MCU v10.5\MCU\Help\PDF
2) You still need to protect that section. The "R - READ" feature is only for the application, I mean that this R tells the compiler to treat the section as read-only. In other words, you are only preventing your code from writing to that section, but it does not mean that the physical memory is protected.
Check the next application note for some basics about security: