Research on the structure of posttraumatic stress disorder (PTSD) symptoms has yielded support for two 4-factor models: the King (King, Leskin, King, & Weathers, 1998) and Simms/Watson models (Simms, Watson, & Doebbeling, 2002). This study evaluated them using data drawn from 1,128 Vietnam veterans by comparing associations with a latent internalizing comorbidity variable and five scales from the MMPI-2 Restructured Clinical (RC) Scales (Tellegen et al., 2003). The Simms/Watson dysphoria factor failed to show evidence of superior convergent or discriminant validity in association with external measures relative to the numbing or hyperarousal factors of the King model. Findings raise questions about proposals to abandon the distinction between numbing and hyperarousal symptoms in favor of a dysphoria-based model.