@akanter - I checked. There isn’t any such global property in Bahmni/OpenMRS. There are some global properties set for openconceptlab, but none of those will answer this question (last time sync from OCL).
Maybe we need a concept in CIEL dictionary which is called: CIEL.version, CIEL.dateUpdated, etc… which can be used to inspect a system and check which CIEL dictionary was downloaded. Will be useful in general in distributed EMR scenario, where they pull periodically from a central OCL server.