Some research on the leather shaves that resemble spokeshaves: bookbinders and other folks who need to shave long bevels on leather have apparently been modifying spokeshaves for some time for their own use. The two most significant changes seem to be: (a) opening up the mouth a lot, with 3/16" being the recommendation I found in one article, and (b) grinding the bevel to 10 degrees, way more acute than on a spokeshave. This little Dunlap I bought isn't configured anywhere near like that, so I think it is a spokeshave for wood.
If I had the time, which I don't, I'd dig around and see if I could find a Sears catalog that included the Dunlap line, to confirm my hypothesis. But that's not necessary to shave wood with it, so I think I'll just let it be.