Warbird Information Exchange

What about different manufacturing facilities for the same manufacturer?

For example, NAA manufactured P-51Ds in both Dallas and Inglewood. Other than specific differences related to their block numbers, would the components of an -NT and an -NA airframe be as interchangeable as those of two -NT or two -NA airframes?

I suppose a key question for any given manufacturer with multiple production lines would be whether the two plants were truly separate manufacturing facilities, or if at least one of them was simply a final assembly plant that pulled from a common pool of components and subassemblies.