POP MUSIC

REUNITED: Actor Richard Dean Anderson, the charismatic blond adventurer on television’s “MacGyver,” stopped in at Humphrey’s the other night to say hello to his old college chum, acoustic guitarist Leo Kottke. Kottke was co-headlining with legendary picker Chet Atkins. . . . When hard-rockers REO Speedwagon opened the Del Mar Fair’s annual Grandstand Stage concert series Thursday night, they found three familiar faces standing on the sidelines: production manager David Wright and two of his stagehands, who in the early 1970s used to pal around with the band on the Champaign, Ill., nightclub circuit.