Tom,
I checked the 1964 Sweets insert and I don't think the DA520 is a match. The photo does not show a contrasting area on the right side of the console, and like I said, the two toggles are not centered top-to-bottom on the console - which would be the typical placement for 2 switches. On this one the lower switch appears to be centered, as it would be if there were 3 switches. Minor quirks, but enough for me to believe the one you identified is not the right model.
lawrence