This one's relatively easy to answer - with, as usual, help from Dr. Thomas Graham's fine book, Remembering Revell Model Kits.
In 1972 Revell issued three kits mounted on "wall plaques." Dr. Graham describes them as follows:
"H-801 USS Constitution wall plaque 1972-75 [those are the years when it appeared in Revell's printed catalogs] $15-20 [Dr. Graham's estimate of the kit's value on the collectors's market, as of the book's publication date of 2004]
"Brown plastic. Includes bottle of gold antiquing wax, thread for rigging. These three wall plaques were based on development materials used for the old full-hull models, but were completely different new molds. They are not just half-hulls, but project out from the plaque slightly. Authentic old maps for the backgrounds. Based on H-319 Old Ironsides.
"H-802 Cutty Sark wall plaque 1972-75 $15-20
"Black plastic. Based on H-317 Stag Hound. [I think this may be a rare error in the book. I'm pretty sure the kit was in fact based on one of Revell's three other Cutty Sark kits - all of which were reasonably accurate representations of the real Cutty Sark.]
"H-803 Spanish galleon wall plaque 1972-75 $15-20
"Brown plastic. Based on H-400."
I never bought any of these kits, so I'm relying on Dr. Graham's book and my own memory of looking at them in the hobby shop where I worked. They constituted one more effort by Revell, at a time when it was having severe financial problems, to stir up some additional interest in (and get additional money out of) its sailing ship line.
It's a pretty safe bet that philo426's kit was one of those three. I can't remember any similar product from any other manufacturer.
Hope that helps.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.