I'm wondering if these two things were allowed by the electrical Code in 1981 in California
There is nothing wrong with striping a wire in a box and attaching it under a screw then feeding a second outlet. I don't do it but have seen it done quite often it saves a few cents for the installer but makes updates tougher.  If the circuit is a multi wire branch circuit this would require the neutrals to be pigtailed and that may be why they are pigtails.