The Structured Interview of Reported Symptoms (SIRS) underwent a major revision in 2010 yielding the SIRS-2. The new test has since been criticized for several potential problems, particularly in terms of its sensitivity to feigned psychopathology. For this reason, the purpose of this study was to examine the concordance between SIRS and SIRS-2 classifications and sensitivity estimates in an archival sample of 263 criminal defendants (215 males, 48 females) who were admitted to a high-security state psychiatric hospital for restoration of competency to stand trial. In a subgroup of 39 presumed feigning patients who elevated 1 or more collateral measures of feigning (primarily the M-FAST) at conservative cutoffs, we found marked discrepancies between the sensitivity of the SIRS (.87) and SIRS-2 (.54). The marked differences in sensitivity were partially explained by a global interpretation discordance rate of 47%, with discordance primarily resulting from SIRS-based feigning cases being classified as indeterminate on the SIRS-2. Follow-up analyses of intercorrelations and percentile distributions indicated that the new SIRS-2 scales may lack utility in the assessment of feigning because of problems relating to the construct validity of the scales and their interpretive cutoffs. Future directions in research and clinical practice are discussed, with added emphasis on the significant limitations of archival pretrial forensic samples for identifying presumed genuine groups necessary to calculate specificity estimates (which were meaningfully higher for the SIRS-2 in this sample). Overall, the primary clinical implication is that feigning should remain a strong consideration in SIRS-2 cases yielding an indeterminate classification.