What's in this Barracuda?

Over a year ago I picked up a Barracuda that was someone's project. They had intended it to be a gasser with a welded diff (which was broken when I got my hands on it) I got it running with a new carb and some minor engine work and replaced the broken spider and ring gears. Now I'm wondering what's missing. The original column shifter linkage has been removed as well as the kickdown levers and it has a B&M shifter installed on the floor. The shifter works well and it easily shifts from 1st to 2nd and D manually. The transmission is a 904. Is there an easy way to tell if a manual valve body has been installed? I'm about to put some money down on a linkage cable to make sure I don't inadvertently kill the transmission.