If by "Thanos nodes" you mean Thanos querier instances, then yes -> Does not matter to which one you actually ask. All have the same view and access to the old

If by "Thanos nodes" you mean Thanos querier instances, then yes -> Does not matter to which one you actually ask. All have the same view and access to the old metrics (Store Gateway) and fresh ones (Prometheus+Sidecar - Scraper)