Hi,
As long as the PIC doesn't have its code protection bit set you should be able to read it with a suitable PIC programmer you are using. The result will be .hex file which, in itself, won't do you much good. It's possible to disassemble the .hex file to get an assembly listing of it but there will be no comments, no variable names, no labels and so on. You would really need to know what you're doing in order to make changes in there.