Where oh where are the interior door locks on the passanger side?!?!

Hello I decided to try my luck today and hopefully receive an answer. Okay this question might seem a little ridiculous but it is very odd and the answer is very essential, you see my boyfriend recently bought a 1978 chevy corvette but we cannot find the interior door lock on the passenger side. The drivers side has the lock inside of the arm rest on that door but the same cannot be said about the passenger side. I have been searching and searching articles and the actual car itself for it but I have not have any luck. If you so perhaps have a response, please comment back I greatly appreciate it (=!
-V