Port, I believe the date was April 30, 1986. The same crew wrestled in Amarillo the night before.
From Nick Roberts' journal, the April 29, 1986 show in Amarillo (and beside it the notes from the following night in Lubbock)...
As you can see, the lineup changed quite a bit from what had been advertised.
It appears this may have been the "final straw" (as you alluded to the many no-shows in another thread,) and thus the final World Class shows promoted by Mr. Roberts. There is a May 25 card listed, but no town and no numbers so I suspect that may have not happened. The next shows were mid-July with UWF talent (many of them former World Class talents -- Freebirds, Fantastics, Kamala)