Hi VirginFlyer, Buzz here. There's a DC-3 web site you might ask, www.douglasDC3.com, Trev might know somebody who can answer the question. There's a large book by Gradige (not the right spelling) that lists all the serial numbers / tail numbers of the DC-3's. I saw a copy of the book once.
Neither of those 2 numbers make a lot of sense to me. I've worked on a couple DC-3's in the last 10 years. One was serial 1997, she's a pre-WW2 DC-3 (N136PB / NC18121) and the other is a converted C-47, serial number 9040 (N84KB).
There were a few different plants constructing C-47's back then, That one might have been from the Douglas plant at Tulsa Oklahoma. The 2 DC-3 that i know well came from the Santa Monica plant and Long Beach plant.
Buzz Fuselsauage: Line Mechanic by night, DC-3 Crew chief by choice, taildragger pilot for fun