A lot of old school tuners either don't really want to bother or sometimes even understand how to tune the vacuum advance. It's more for driveabiltiy and mpg. So they eliminate it and only run mechanical. Could be what happened on yours.
If it's not hooked up, then you should have a vacuum leak, which should be noticeable by how the engine runs. That would be a clue as to how it was setup before you messed with the trans.
