I was reading through the specifications chapter in John Bridges' Studebaker's Finest when I discovered something--according to my body serial number (and my engine number) my car WAS built at the Los Angeles plant.
My body serial number falls within the Los Angeles range that starts with G-917,701 and ends at G-927,400. My engine serial number is also a US plant serial number.
I'll run this past the guru's on the Studebaker Driver's Club forums, but I'm wondering if the records at the Studebaker National Museum have lapses with the Los Angeles cars as well as the Canadian models?
Update: the folks on the forum agree with me that it is a Los Angeles car, and have double-checked the serial number range with another source. I've been encouraged to contact the Studebaker National Museum again as they should have complete records from that period for the Los Angeles plant.