Occasionally it’s a shock to find out what material can be turned into a hit Broadway musical. Who would have thought the intensely financial travails of Alexander Hamilton would become singable content? This Saturday at 2 the deYoung Museum is sponsoring a lecture at Koret Auditorium on just how true to facts “Hamilton” really is. It’s led by historian Richard Bell and part of programs that are offered every Saturday free to San Francisco residents. Why not give it a shot?