Correct.
If you have 3 Take Inventory in your graveyard, and 3 harness the storm in play:
1) Cast Take Inventory #4, put it on the stack.
2) Put 3 Harness the Storm triggers on the stack targeting 3 different copies of Take Inventory in your Graveyard.
3) Both players pass priority.
4) First Harness the Storm resolves, casting Take Inventory (Paying 1U), which adds it to the stack.
5) Pass Pass
6)Take Inventory resolves, seeing 2 Take Inventories in the Graveyard [Draw 3].
7) Pass Pass
8) Second Harness the Storm resolves, casting Take Inventory (Paying 1U), which adds it to the stack.
9) Pass Pass
10) Take Inventory Resolves, seeing 2 Take Inventories in the Graveyard [Draw 3]
11) Pass Pass
12) Third Harness the Storm resolves, casting Take Inventory (paying 1U), which adds it to the stack.
13) Pass Pass
14) Take Inventory Resolves, seeing 2 Take Inventories in the Graveyard [Draw 3]
15) Pass Pass
16) Initial Take Inventory Resolves, seeing 3 Take Inventories in the Graveyard [Draw 4]
4UUUU: Draw 13 (Totally a coincidence yo)