BOSS BLUES: Chicago’s foremost blues label, Alligator Records, is celebrating its 20th anniversary with a 35-song, double-CD collection that features a host of classic tracks from the company’s vaults. Highlights include the label’s debut release, Hound Dog Taylor’s “Give Me Back My Wig” and Carey Bell and Junior Wells’ “Second Hand Man,” plus songs from James Cotton, Professor Longhair, Koko Taylor, Elvin Bishop, Albert Collins, Delbert McClinton, Son Seals, Lonnie Brooks and Big Twist & the Mellow Fellows. . . .Guitarslinger Buddy Guy has signed with RCA/Silvertone Records. His upcoming album, “Damn Right I’ve Got the Blues,” is slated to feature guest performances by Eric Clapton and Jeff Beck. . . . Meanwhile, a tip of our blues cap to Charisma Records, which is now distributing Point Blank Records, a British-based blues label that has quietly been signing a host of contemporary bluesmen (including many former Alligator artists). The label makes its U.S. debut this week with new releases from Albert Collins and the Kinsey Report, with more records on the way from Johnny Winter, New Orleans-based pianist Walter (Wolfman) Washington and Chicago guitarslinger Dion Payton.