The smb.con file dates back to when Apple still used the standard open-source SAMBA software. When Apple released Mac OS X Lion they switched to using their own smbx software instead of SAMBA. This was due to SAMBA switching to GNU 3.0 Licensing which Apple felt unable to comply with.
So /etc/smb.conf no longer exists at least on Macs.
The nearest equivalent for Apple's own proprietary smbx software would be either /etc/nsmb.conf or ~/Library/Preferences/nsmb.conf
The first is the global settings file for the entire computer, the second is stored in each users home directory.
Note: The contents of this file are totally different to what was in /etc/smb.conf
I recommend you run Terminal.app and type man nsmb.conf for information about this file.
While the above Unix man page shows very few options and none of the ones you list, it is possible some options are not documented.