When might a module's weight in the system table not affect its hook order?
If revisioning does not appear in the system table, it is considered not installed and hook implementations it provides are not executed.

Upon installation, the revisioning module updates its weight to 1, making its hook implementations run later than those of most other modules (which default to a weight of 0).

If you want to change the order in which implementations of a particular hook are executed, have a look at hook_module_implements_alter().