Change Gateway in the Setup

In my precedent answer, I suppose eth0 as RED, and eth1 as GREEN...
But it's not forbidden to make eth0 as GREEN, and eth1 as RED... In this case, the modem routeur is not, as you suppose 192.168.1.0, but 192.168.1.253.

In never do the setup this way ( I always done a NetServer setup on a minimal CentOS), so I ask:
At this step, is the rules ( Red, Orange, ..) are already done, or not yet?