Dead with the Allman Bros

I am trying to track down a show for a friend who says he saw them play together between 71-73 in the Hartford area. I checked Hartford Civic Center but their first show there was 77. Any ideas?

5/7/77

I've had problems finding posters for some shows. Should I assume they don't exist? Screen comes up page cannot be found while others pop right up. I've been downloading shows from archive.org for my brother (just turned 50 and I -46) and its great adding the ticket stubs to the shows he was at and