No; I took Mandalore and HK-47 with me to Onderon in the Basilisk. Kavar walks out, says "This ends here, Vaklu!", stuns the soldiers, and then has his I-won't-answer-your-questions dialogue with the Exile. As soon as he and the PC begin to fight, Mandalore and HK disappear from my party and I'm fighting him solo.
Thank you Gorgod.