Sounds like a one microphone recording in someone's living room. Great! The song "Soy Aurinegro" is known as "Si, si, señores" at many other clubs in South America (see Boca on this site), but according to the book "Historia de Peñarol" (L. Alvarez) it was composed and first released in 1961 for Peñarol. There were two different versions of this song and single.