Not just common on bucket seats from the 60's and older. I remember 2 door cars from back in the day with the split front bench seat backs that tilted forward in order to access the back seat also did not lock either.
good to hear! I can't wait to insall them. I am gonna pull the car up and take off the carpet and get some aluminum spaces for now and install the seats. I'll take the spacers later and make better ones. There is a really helpful article in the tech article section on installing the seats too.