The movement mounts (in the case) for the V72 are in slightly different locations than for the 7750, so the cases are not really swappable.
Unless you can manufacture very intricate mounting bridles that account for the differing mounting locations, you need to fit your movement into the correct case.
If you have a V72, you need a case made for a V72. If you have a 77xx, you need a case made for a 77xx.