it depends on the regulator but on my victor regulator when my safety popped there was no way i was able to disassemble it. I had to get it rebuilt from a guy that fixes welding equipment for 50 dollars but afterwards it worked like it was brand new and should last a lifetime.
If you have a nice regulator then it's worth it to get it repaired but if not then i don't think it's worth it. You can find some pretty good dual stage regulators online for about 50 dollars.