After a little bargaining a price was arrived at that made everyone happy (things started just north of $125.00, but ended at $100) and away I went. Once home the two pieces were separated and lightly sanded.
Though it isn't obvious in this photo, the existing backing from the hutch's top-half was flimsy, stained and worn; in need of replacement and removed.
A quick coat of water-based primer on everything is next followed by two coats of a low sheen, water-based enamel (often called an 'Eggshell' finish, some prefer 'Satin' though the 'Eggshell' is just slightly more durable I believe)...
Using small steel zinc-coated finishing nails versus even a medium-duty staple is more precise and yields not only a more sturdy, but a more lasting result. I used the smaller size in each of the corners, and to 'place' the backing, then the slightly larger size for the securing the ramaining area (one nail every 8 inches is adequate), following the pattern made by the back of the upper piece's frame, and the rear edge of each shelf.
Once the backing is attached it's time to see what they look like after being taken inside and 're-assembled'!
The intent of the second image here, was to try and show a little more of the linear texture of the 'wainscotting-board', the new backing...
And finally, viola, all done (finito!).