The 720 doesn't come with a firmware update for Denim, it's just OS v 14219. If you're already on that OS then you already have the Denim release. Tinkering with the PfD is not going to update your phone further.
If you are sure that your country variant is India you have 2 options.
1 Wait, but leave the pfd box unchecked.(if you are on pfd than you will not get that much extra with denim)
2 Use the Lumia Software Recovery tool (i know you do not really want to do this)