Here are a couple of old posts that should shed some light on this subject.
Hardy Chicago is a variety that is typical of the fig trees grown in the area around Mt. Etna, Sicily. These trees were brought to the America by Italian immigrants many years ago. The variety "Hardy Chicago" was first distributed by Fred Born, who discovered the tree growing in the yard of an Italian immigrant in Chicago (see Ray Givan's New Fig Booklet for details). I agree with Jason that the tree that Dave found closely resembles Hardy Chicago. It could be Hardy Chicago. It could be a closely related fig from the same area in Italy.
All these Hardy Chicago type figs that are popping up may turn out to be the same variety just exhibiting different traits when grown in different areas. They may all end up being closely related but unique varieties. Or they may end up being different strains of one variety that are only very slightly different from each other.
The unknown that I have that I've called Joe's Jersey is from a tree that was planted well before Hardy Chicago was in trade as a named variety. The leaves, growth habit, and fruit look almost identical to Hardy Chicago. But the tree starts forming fruit earlier in the season than Hardy Chicago and the fruit has a different flavor than Hardy Chicago. Only a close comparison over several seasons will tell if Dave's tree is Hardy Chicago, a new strain of Hardy Chicago that is only slightly different, or a closely related variety.
And to add to the confusion there may be a few different varieties that are in trade under the name Hardy Chicago. Oh the world of figs...