For the use of ku/bos to mean the one-spot or ace on ancient dice, see kappa 2602. The proverb for high risk gambling is explained at tau 1006 and eta 635.
The present headword noun (here in the accusative plural) derives from an Indo-European root used for 'one' in several language groups, e.g. Latin unus and the Germanic relatives of English 'one', but not in most Greek dialects. It seems therefore not to be a borrowing from Latin but a survival in the Ionic dialect. See also tau 1005 and LSJ s.v.