A Catalog-Level Test of Spacing Nulls and 70:30-Class Dynamic Balance in Gamma-Ray Spectral Residuals

We perform a catalog-level test of residual structure in gamma-ray spectral energy distributions using selected Fermi-LAT catalog sources with valid multi-band spectral information. The working sample contains 732 sources and 4413 valid standardized band residuals. A smooth catalog spectral baseline is constructed for each source using the reported spectral model, and standardized residuals are formed in logarithmic flux space. Two residual-structure hypotheses are tested. First, a compact single-ratio spacing hypothesis is examined using positive local maxima. The spacing test is not supported and is classified as a catalog-grid-limited null result. Second, signed local extrema are analyzed by combining positive local maxima and negative local minima. While the global residual field remains nearly sign-balanced, localized energy-band windows show positive-dominant extrema fractions approaching a 70:30-class regime. The results suggest that a globally near-balanced residual field can reorganize under signed-extrema selection and energy-band localization toward a positive-dominant dynamic-balance candidate. The study does not establish a universal spacing law or a global 70:30 law, but motivates the 70:30 attractor hypothesis as a testable framework for future high-resolution gamma-ray residual studies.