Capt. Stieben
1.)Cork gunning decoys have been made with, and without tailboards (same goes for bottom boards) since their inception. Boils down to personal preference, local tradition, and use.
2) As Jim Schmiedlin said "Decoys are vessels." Their are many types of vessels, and there are many types of cork decoy shapes.
Bean Coastal Decoys are large flat decoys, with a low center of gravity, made for big water gunning. They do not self right, and have no need to. Some folks scoff at their style and side view, but from a birds eye view they Work.
Over many years I have made/rasped decoys from all types of cork. Some have tailboards and bottom boards, some don't. Others have been covered with linen. Many were made for big water use, marsh use, and light weight for "walk in" use. Size and shape varies. All work just fine, and are always ready to go to work.
This life vest cork Coot was made for my "walk in" small rig. It has a thin bottom board, no tailboard, and is coated with a cork dust and Spar Varnish slurry. It does self right and the ribbon was a bonus. It has it's own decoy bag and is stuffed in the canvas duffel bag I have used for many years.
The GW Teal were made for a friends walk in rig.
just my 2 cents worth
If you need any help making your own decoys there are many high quality decoy makers/carvers here to get you on your way.
I wish you well.
View attachment coot cork naked.jpgView attachment coot cork with slurry.JPGView attachment coot finished outdoors.jpgView attachment cork green wing teal 2013.jpgView attachment cork gwt complete pair 2013.jpg