This record releases v1.0.0 of the closeout/robustness note for late‑time value selection of the effective cosmological constant on the GR‑exact, flux‑fixed branch of the Gauged Constant Vacuum‑Mode (GCV) framework. The analysis works with the dimensionless ratio x ≡ Λ/Λ_obs and starts from the fixed v6 capability‑conditioned posteriors defined in the archived v6 bundle. What this note does Quantifies the baseline Step‑6 behavior (mildly skewed above unity; DETECT has a large high‑x tail). Provides an explicit three‑bottleneck closeout mechanism (not presented as a unique cosmological measure) that yields a pronounced near‑unity interior peak and strongly suppressed tails under modest parameter variation. Defines a fixed, quantitative acceptance gate for UV‑derived, GCV‑compatible “derived‑Λ” candidates, expressed in four metrics:med_M, med_D, P_band ≡ P(0.8 5), including “minimum pass” and “Target” thresholds. Headline numbers (recommended configuration) Baseline Step‑6: medians ~1.44 (MEASURE) and ~1.62 (DETECT), with a large DETECT high‑x tail. Closeout instantiation: medians ~1.05 (MEASURE) and ~1.00 (DETECT) with P(0.85) ~10^-5–10^-4. What’s included in this Zenodo upload The manuscript PDF + LaTeX source. A minimal reproduction script and the minimal posterior grids needed to validate the closeout summary numbers (see README in the archive). Scope / claim boundaryThis note does not claim a UV first‑principles prediction of Λ_obs or a unique cosmological measure; it provides a fixed acceptance gate and an explicit, disciplined closeout construction to make the next UV stage falsifiable. Project homepage: https://johansson.digitalProject overview hub: https://github.com/gcv-framework/gcv-vacuum-energy