Valjoux bought out Venus and spun the Vj7730 then 7731 off of the Venus 188. Then they decided they needed a family of movements to replace the 72 and 92, capable of being manufactured more cheaply and quickly, giving Valjoux better margins than their older movements.

So we end up with a range including, as used by Heuer:

7733 - 2 register
7734 - 2 register with date
7736 - 3 register

They were designed with as much commonality as possible, unlike the 72 and 92 where any commonality was as much serendipity as it was deliberate design. The result is that more than 90% of the components are shared amongst the 3 movements, which also means that when you look at the back side of the movement, as you just have, one looks very much like another.

So your 7733 looking like a 7736 is just as it should be :)