This was the first show in the USA. As the band had problems to get to Philadelphia in time they arrived too late. So they were only able to play four songs before curfew.
Hugo Burnham remembered:
" The first ever US show we did was the night before Boston - at The Hot Club in PHiladelphia. Our van broke down coming out of NYC (Squeeze had put water in the gas tank when they left it for us) and we didn't get there until midnight and played about 4 songs on someone else's equipment before the curfew. The band took a train up to Boston the next morning, our manager, Rob Warr, and roadie (my brother, Jolyon) drove up with a guy from Philly called Tom Potts, who joined the tour as driver for the next ten days."
The date might be the right one. Pylon are listed to be the support of Gang of Four that night. You can find the site about this information here.