The two angled blades in the centre are not from a plough plane. They appear to be from a wooden rebate plane and although they cut a horizontal line, are mounted in the plane on a skew, hence the angled end. These blades (in the UK at least) rarely bear makers names. Even so, they could originate in other types of speciality planes - dovetail, or library-shelf planes spring to mind; it's hard to tell without the original item.
Plough plane irons on their own, usually refugees from broken planes, are quite common on the second hand market on this side of the Atlantic, but according to some folk I have read about, tend to be rare in the US. Their value as a matched set from the same plane and maker tends to be greater than a 'harlequin' set made up from different sources because the angle of taper along the blades should be the same so that it matches the wedge and are interchangeable. Not a good idea to split a matched set - affects the value drastically.
The backs of the irons were usually a flat billet of very hard steel forged onto a softer iron body for strength. The sneck at the end is very soft and will deform, therefore they do make good chisels, even when handled (they bend). If you don't want to recreate a plough plane, they do, however make excellent hand router blades, as this blogger has done:
http://lumberjocks.com/projects/100861
All best from Wales