Not true for me. My c section was scheduled at 39.2 weeks I went into labor at 38.2 weeks and was able to try and do natural but in the end I ended up with an emergency c section. You can always ask your dr.
If you go into labor before your csection they will just do your csection then ..
I'm pretty sure if you fo into labor and you have scheduled c section, they continue with the c section. Unless it all happens so fast. I would talk with your Dr.