Just test, that is probably the quickest.
Try listing /proc/sys/fs before doing the insmod and after doing the insmod.
I don't think you have to create the directory (which is part of the module code) and I don't think you have to mount it (it did have to be mounted in the kernel 2.4.x days).
And I expect that a rmmod will make it all go away again.
You should find the "binfmt_misc" directory in the source code for the module as something like:
const char = "binfmt_misc"
Possible hidden inside a macro.
In the article linked to about luajit, I don't see any mkdir or mount commands.
But they are not clear about what parts of the system setup their distribution had automated for them. (The author might not even have known about distribution specific automation.)