Punktaku, crazy thing, it still wasn't there, but then I realized there are 2 options when you set up the gang under Gang Manager: Goliath (GotU) and Goliath (HoC)
You need to select HoC to see Gene-smithing in the equipment drop down.
So for future reference for anyone with the same problem:
1. From the home menu select: Necromunda: Underhive Tools
2. Next screen will show N18 in the top right corner to the left of the gear. Now select "GANG MANAGER" button under TOOLS
3. On the next screen, from the "QUICK GANG CREATE", drop down menu select: Goliath (HoC)
Now when you add fighters you will see the Gene-smithing drop down option Punktaku shows in his screen shot above.