A companion study to Part I of a fifth racetrack applying random matrix theory (RMT) to Earth's spatial rhythms (Spatial Level Repulsion in the Stratigraphic Record, Zenodo 20774581). The nontrivial zeros of the Riemann zeta function follow the Gaussian Unitary Ensemble (GUE) of random matrix theory (the Montgomery-Odlyzko law). Part I showed that the down-core spacings of Milankovitch cycles in real cyclostratigraphic sections also reach the GUE class. This companion places both on the same scale and asks, with purely real data on both sides, whether they are statistically isomorphic. Target A is 4520 real Riemann zeros (imaginary parts) computed by David Platt and archived in the LMFDB, decoded from the native Platt binary format and verified against the published Odlyzko values. Target B is the two independent real cyclostratigraphic sections established in Part I: the Gubbio Contessa magnetic-susceptibility section (PANGAEA 864450) and the Blue Lias section (PANGAEA 896875), processed by the same validated spatial-RMT pipeline. The 4519 real zero spacings give a spacing ratio of 0.617, essentially the theoretical GUE value (0.603), confirming the method. Both strata sections are systematically more rigid than the zeros: 0.735 for Gubbio and 0.748 for Blue Lias, higher by +0.12 and +0.13. The statistical resolution of this difference depends on sample size. With Gubbio alone (31 spacings) a two-sample Kolmogorov-Smirnov test cannot reject equality with the zeros (p = 0.65). But the larger Blue Lias section (98 spacings) does reject it (D = 0.145, p = 0.031), as do the two sections combined (129 spacings, p = 0.037). Honest conclusion: both belong to the GUE universality class - a real and deep statistical-physics correspondence, the same kind Montgomery and Dyson found between primes and atomic nuclei - but they are not the same distribution. Two independent astronomically forced sections, from different basins, ages, and lithologies, sit measurably closer to the rigid-lattice limit than the zeta zeros, and with enough spacings this difference is statistically significant. That two unrelated sections show the same rigidity offset indicates it is a general property of astronomically forced strata, the signature of an external periodic clock that is more regular than the GUE. Same key (GUE), not the same melody: the strata are more rigid. Sharing a universality class does not imply any causal or ontological link between primes and strata; universality is precisely the statement that microscopically unrelated systems can share macroscopic statistics. Includes a reusable decoder for David Platt's native binary zero format. A companion to, not Part II of, the racetrack.
Ruqing Chen (Sat,) studied this question.