to tow or not to tow a 727

Do it the safe way and disconnect the driveline.

The problem comes from towing an excessive amount of miles with no lubrication to the output shaft bushed components.
A few (10 or so miles) won't hurt it, but I wouldn't try more than about that without disconnecting the driveline on any RWD.

Now on a new rebuilt, I wouldn't risk it at all.
It's only four little bolts and a section of coat hangar wire.