I spotted this Equus poster at the Antique Marketplace here in Austin. It's a reasonable price, but still out of my range. It was cool to see a piece of 70's ephemera like this hanging between a shelf of English silver and a Chippendale style settee.
Gilbert Lesser's best known work is the Studio 54 logo, but he also designed posters, costumes and stage sets for the theater.
More here: NYT Obit Link
Better quality image of Equus poster from MoMA/FFFFOUND!