R20 and RT15I tweeters

Anyone know if these are interchangeable.
McCormack DNA-1 Amp, Parasound Halo P5 Pre Amp, Denon DVD 2900 CD player, Adcom GDA 700 DAC, VPI Traveler TT with Denon 103R cartridge, Lounge Audio MKiii phono pre and Copla SUT, Polk SDA SRS 3.1 TL speakers, Tributaries series 8 IC's and speaker cable.