factory shifter is fine. I used one for years with the rod to the column not connected. I drag raced it and drive it like this for 16 years before switching to a 5 speed. I would leave it as is and work on other more important things. like putting the dash togethor and getting that steroe mounted.
The dashboard and stereo were mounted but I had to take them off to replace the brake light switch..I am going to install my left front speaker first and then I will assemble everything together
I would try putting the floor shifter back together. They work fine when they are as they should be. If that bushing fell out next to the column, that might have lead the PO to convert to the cable, because he couldn't figure out how to unstick his key either ...