Scott, the service was 240V, one phase fed one plate, & the other phase to the other plate... The service record dated back to the early 80's not much use in timelining! LOL.... This was in fact, in Newport Beach! Right off Balboa Bl. I didnt know there were houses that old there either! but the homeowner said the house was built in 1935.
Sven, Its Cutler Hammer... Ironically, the replacement I got for the bad set I pulled out was Square D, but all the patent numbers were the same to the CH... Did electrical mfr.'s do work a little different back in the day? These were all 20A circuits BTW...
LOL On the emblem colors... Ya think?