I have looked up in my c47/DC3 ex USAAF manual and can confirm that the firing order was1,10,5,14,9,4,,13,8,3,12,7,2,11,6..
I worked on the Dak for about 3 years in the mid 50s for B.E.A. and enjoyed every minute once you had the right tools they were very easy to work on.