If it's a new character on a NEW server, u won't get it. Legacy is ONLY server based, so you'd have to start a COMPLETELY new one on the new server.

A small clarification, cause I got confused on this also. When you Unlock those Companion Legacy buffs, they buff YOUR stats, the character, NOT the companion. Cause I did them on mine and I got the 1% surge one for example and my surge, my main character, is now at 51% (Am full tank gear and tank spec so no surge on my equipment) Hope that helps clarifies some things cause it confused me as well