Recent studies of the crystallization of cyclotrimethylene-trinitramine (RDX) have shown that the presence of the alpha- and beta-phases of the compound is sensitive to the substrate when using drop cast crystallization methods. The specific phase has potential consequences for measurements of the nitrogen K X-ray emission spectrum (XES) that were recently reported for this compound using samples crystallized on In metal substrates. We have determined that the crystallization of RDX on a clean In metal substrate starts out completely as the beta-phase but progressively incorporates the alpha-phase as the film thickens. In addition, we have carried out additional molecular orbital calculations of the N Is X-ray fluorescence from the valence band, comparing the results expected from the alpha-and beta- phases. The differences due to the presence of the beta-phase instead of, or in addition to, the alpha-phase appear to be minimal.