Absolutely. It's certainly not mounted automatically after Linux boots and depending on the system's configuration it might never get mounted at all. Maybe it could even use some other path.

One of my long term goals with the programming language I posted is to boot Linux directly into the interpreter and bring up the entire system from inside it. Not only will /proc not be mounted, my program's gonna be the one that mounts it. So I decided to avoid using tricks like reading /proc/self/exe.