Hint - HK47 does the factory on his own so make sure he is fully equipped before you head to Dantooine and the meeting with the jedi masters. Step 4 - At the appropriate point during the end game you are taken to the HK factory. Step 3 - Keep scrapping teams of HK50s until, upon returning to the Ebon Hawk, you get a cutscene (you'll know when you get it, it is rather interesting - if you like HK47 that is). Step 2 - IMMEDIATELY upon activating HK47 have the initial conversation with him, then start a second conversation and explore the dialogue options until you find the sequence about the sonic imprint sensor.
So go where you like, you'll get the parts for HK47 quick enough.
Works the same as the base game except TSLRCM has more teams of HK50s scattered across the planets from which you can obtain HK47's parts.