Excellent question. We would need to establish a chronology of Andrew's gigs, something like the Art Blakey chronology at jazzmf.com. The Hill discography at jazzdiscography.com can help, but there are probably not a whole lot of gigs from the 60s listed.
Ideally, one would need access to a database of jazz journals such as ripmjazz.com but you need some institutional affiliation. Alternatively, a person with a collection of downbeats from the 60s could look up all the gig listings.