I guess that would qualify as a ship lap joint but that only means one piece overhangs the other.
Walter, for use with your router a vertical panel raising bit is the right choice. The smaller diameter requires less power than the large horizontal panel raising bits. Do not attempt to remove all the material in one cut. This should be cut in stages removing no more than 1/4" of material per pass. In other words set the bit for a partial cut, run your boards, adjust the depth of cut and go again. Give your router regular breaks since this is heavy material removal, let it cool down after a couple boards. This will also prolong bit life. The small chamfer on the rabbet can be done with a V bit.
You can view a large selection of bits at reasonable prices at MLCS.com
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