Except for PD dvds- there are no legit Republic serials on DVD.
Is that also true of VCI's release of DRUMS OF FU MANCHU?  (They've released a handful of serials from both Republic and Columiba.)  Slightly off-topic, I know the character of Fu wasn't allowed to lapse into PD.  Until his death last year, Harry Alan Towers still held the film rights to Rohmer's Fu Manchu and Sumuru characters.  I think his widow, actress/producer Maria Rohm, still has the properties.