I unlocked Hk at lvl 12 or 14 when I was on dromund. I bought a blue sniper rifle and left his lvl 50 gear on. He did pretty good damage and took hits well. I'll have to wait till lvl 50 to put his orange sniper rifle back on. His armor seems to work even though its lvl 50 and im lvl 16 now on balmora.
As for the ship it wont matter if you get HK early you just cant talk to him untill you get your ship, and now you will have an extra crew early for crafting missions.
From everything I've read, he gets no stats from that gear. It's more likely he's benefiting from the presence boosts you've gotten from previous toons. With 4 50's plus the human presence boost, I was fairly unstoppable even with Khem Val in rubbish gear.
It will be nice to have enough companions to send out on missions for a change. Seems like I never have enough companions to keep the maximum # deployed until late in the game.