Well did a little more reading and the author of Unison does not provide any binary file period.

Some other users have compiled versions though for other operating systems including Windows.

Just poor documentation on the site (IMHO) - makes you do too much reading to find what you need.

They have a GTK version that does require the libraries but according to the older docs the TEXT version in the tar is usable stand alone.

Download Unison-2.27.57-Gtk.zip
This contains both versions, command line and the GUI but you only want or need the command line TEXT which is named Unison-2.27.57 Text.exe