No. They may or may not have been the ancestors of humans (various sources suggest this), but they are not humans per se, so no. The question, "are the humans forerunner?" may yield different results.
Actually. The forerunners we're a race of super intelligent beings who once WENT TO WAR with super advanced humans. The reason humans are how they are in the halo series was because the humans lost and we're deevolved into...Modern Humans rather than intersteller war mongers. They we're also allys with who would be the prophets, the san'syum (Excuse my spelling on that part).