Mopar Muscle Association UK

Hi all, need advice on a pair of 1970 highback seats, b body. They have a push button on the side of the seat that moves ok when pressed, but I took the back off both and there is no mechanism behind the buttons, they don't lock in the upright position so tilt forward without having to depress the button, I think there must be parts missing or is this factory?
Cheers guys,

If they are like my 71 Ebody, the locking pawls are inside the lower part of the back rest, the button just acts against the mech when pushed.
its not the best system tbh!
mine only lock on one side, with a square locking toggle bolted to the lower part of the seat,

Thanks for the insight, I had highbacks in a previous 69 I used to own, the empty passenger seat would fold forward under heavy braking, really irritating! need to look inside them a bit closer I reckon.